diff --git a/gdk4-wayland/src/auto/versions.txt b/gdk4-wayland/src/auto/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4-wayland/src/auto/versions.txt
+++ b/gdk4-wayland/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4-wayland/sys/versions.txt b/gdk4-wayland/sys/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4-wayland/sys/versions.txt
+++ b/gdk4-wayland/sys/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4-win32/src/auto/versions.txt b/gdk4-win32/src/auto/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4-win32/src/auto/versions.txt
+++ b/gdk4-win32/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4-win32/sys/versions.txt b/gdk4-win32/sys/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4-win32/sys/versions.txt
+++ b/gdk4-win32/sys/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4-x11/src/auto/versions.txt b/gdk4-x11/src/auto/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4-x11/src/auto/versions.txt
+++ b/gdk4-x11/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4-x11/src/auto/x11_device_manager_xi2.rs b/gdk4-x11/src/auto/x11_device_manager_xi2.rs
index ba9b7f6d2df9..bd6b9999fd00 100644
--- a/gdk4-x11/src/auto/x11_device_manager_xi2.rs
+++ b/gdk4-x11/src/auto/x11_device_manager_xi2.rs
@@ -84,6 +84,7 @@ impl X11DeviceManagerXI2Builder {
     /// Build the [`X11DeviceManagerXI2`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> X11DeviceManagerXI2 {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gdk4-x11/src/auto/x11_device_xi2.rs b/gdk4-x11/src/auto/x11_device_xi2.rs
index a7a75eeee26c..3ac52ad6eaa8 100644
--- a/gdk4-x11/src/auto/x11_device_xi2.rs
+++ b/gdk4-x11/src/auto/x11_device_xi2.rs
@@ -103,6 +103,7 @@ impl X11DeviceXI2Builder {
     /// Build the [`X11DeviceXI2`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> X11DeviceXI2 {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gdk4-x11/sys/versions.txt b/gdk4-x11/sys/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4-x11/sys/versions.txt
+++ b/gdk4-x11/sys/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4/src/auto/cursor.rs b/gdk4/src/auto/cursor.rs
index 2b37e5973591..ba7fde592e67 100644
--- a/gdk4/src/auto/cursor.rs
+++ b/gdk4/src/auto/cursor.rs
@@ -138,6 +138,7 @@ impl CursorBuilder {
     /// Build the [`Cursor`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Cursor {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gdk4/src/auto/versions.txt b/gdk4/src/auto/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4/src/auto/versions.txt
+++ b/gdk4/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gdk4/sys/versions.txt b/gdk4/sys/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gdk4/sys/versions.txt
+++ b/gdk4/sys/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gsk4/src/auto/gl_shader.rs b/gsk4/src/auto/gl_shader.rs
index 85f8a0a5d0f4..80ba2e5dadd1 100644
--- a/gsk4/src/auto/gl_shader.rs
+++ b/gsk4/src/auto/gl_shader.rs
@@ -228,6 +228,7 @@ impl GLShaderBuilder {
     /// Build the [`GLShader`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GLShader {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gsk4/src/auto/versions.txt b/gsk4/src/auto/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gsk4/src/auto/versions.txt
+++ b/gsk4/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gsk4/sys/versions.txt b/gsk4/sys/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gsk4/sys/versions.txt
+++ b/gsk4/sys/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gtk4/src/auto/about_dialog.rs b/gtk4/src/auto/about_dialog.rs
index 71487b6238cb..fcdc48b3ca77 100644
--- a/gtk4/src/auto/about_dialog.rs
+++ b/gtk4/src/auto/about_dialog.rs
@@ -1212,6 +1212,7 @@ impl AboutDialogBuilder {
     /// Build the [`AboutDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AboutDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/action_bar.rs b/gtk4/src/auto/action_bar.rs
index d86850c79273..d9d1d0d99054 100644
--- a/gtk4/src/auto/action_bar.rs
+++ b/gtk4/src/auto/action_bar.rs
@@ -329,6 +329,7 @@ impl ActionBarBuilder {
     /// Build the [`ActionBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ActionBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/adjustment.rs b/gtk4/src/auto/adjustment.rs
index 66a0a96126a0..0143b5a8b2f2 100644
--- a/gtk4/src/auto/adjustment.rs
+++ b/gtk4/src/auto/adjustment.rs
@@ -115,6 +115,7 @@ impl AdjustmentBuilder {
     /// Build the [`Adjustment`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Adjustment {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/alert_dialog.rs b/gtk4/src/auto/alert_dialog.rs
index 3407706ce2fc..3c280423875e 100644
--- a/gtk4/src/auto/alert_dialog.rs
+++ b/gtk4/src/auto/alert_dialog.rs
@@ -426,6 +426,7 @@ impl AlertDialogBuilder {
     /// Build the [`AlertDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AlertDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/alternative_trigger.rs b/gtk4/src/auto/alternative_trigger.rs
index 687a43ae3e15..2dcc8dee18b7 100644
--- a/gtk4/src/auto/alternative_trigger.rs
+++ b/gtk4/src/auto/alternative_trigger.rs
@@ -97,6 +97,7 @@ impl AlternativeTriggerBuilder {
     /// Build the [`AlternativeTrigger`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AlternativeTrigger {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/app_chooser_button.rs b/gtk4/src/auto/app_chooser_button.rs
index c8276400749e..357a937aacbe 100644
--- a/gtk4/src/auto/app_chooser_button.rs
+++ b/gtk4/src/auto/app_chooser_button.rs
@@ -607,6 +607,7 @@ impl AppChooserButtonBuilder {
     /// Build the [`AppChooserButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AppChooserButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/app_chooser_widget.rs b/gtk4/src/auto/app_chooser_widget.rs
index d33b8d2d5ce6..9aea93dbb953 100644
--- a/gtk4/src/auto/app_chooser_widget.rs
+++ b/gtk4/src/auto/app_chooser_widget.rs
@@ -644,6 +644,7 @@ impl AppChooserWidgetBuilder {
     /// Build the [`AppChooserWidget`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AppChooserWidget {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/application.rs b/gtk4/src/auto/application.rs
index 5e58259f827d..183a193c538a 100644
--- a/gtk4/src/auto/application.rs
+++ b/gtk4/src/auto/application.rs
@@ -101,6 +101,7 @@ impl ApplicationBuilder {
     /// Build the [`Application`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Application {
+        assert_initialized_main_thread!();
         let ret = self.builder.build();
         {
             Application::register_startup_hook(&ret);
diff --git a/gtk4/src/auto/application_window.rs b/gtk4/src/auto/application_window.rs
index 122b8231b08a..349e7ca927cd 100644
--- a/gtk4/src/auto/application_window.rs
+++ b/gtk4/src/auto/application_window.rs
@@ -417,6 +417,7 @@ impl ApplicationWindowBuilder {
     /// Build the [`ApplicationWindow`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ApplicationWindow {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/aspect_frame.rs b/gtk4/src/auto/aspect_frame.rs
index b92d9ccad4d5..bbf8c91fa25b 100644
--- a/gtk4/src/auto/aspect_frame.rs
+++ b/gtk4/src/auto/aspect_frame.rs
@@ -475,6 +475,7 @@ impl AspectFrameBuilder {
     /// Build the [`AspectFrame`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> AspectFrame {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/assistant.rs b/gtk4/src/auto/assistant.rs
index 3c25dd5a01d6..9323ff2d84c1 100644
--- a/gtk4/src/auto/assistant.rs
+++ b/gtk4/src/auto/assistant.rs
@@ -830,6 +830,7 @@ impl AssistantBuilder {
     /// Build the [`Assistant`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Assistant {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/bool_filter.rs b/gtk4/src/auto/bool_filter.rs
index 90f2561e68f6..4856234c9e0f 100644
--- a/gtk4/src/auto/bool_filter.rs
+++ b/gtk4/src/auto/bool_filter.rs
@@ -159,6 +159,7 @@ impl BoolFilterBuilder {
     /// Build the [`BoolFilter`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> BoolFilter {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/box_.rs b/gtk4/src/auto/box_.rs
index fcac20fd7145..cb16f488c261 100644
--- a/gtk4/src/auto/box_.rs
+++ b/gtk4/src/auto/box_.rs
@@ -286,6 +286,7 @@ impl BoxBuilder {
     /// Build the [`Box`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Box {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/box_layout.rs b/gtk4/src/auto/box_layout.rs
index a1b95aa1662e..21f00ebc5c87 100644
--- a/gtk4/src/auto/box_layout.rs
+++ b/gtk4/src/auto/box_layout.rs
@@ -262,6 +262,7 @@ impl BoxLayoutBuilder {
     /// Build the [`BoxLayout`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> BoxLayout {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/button.rs b/gtk4/src/auto/button.rs
index 5f25ae8d8d94..538b6d4c920c 100644
--- a/gtk4/src/auto/button.rs
+++ b/gtk4/src/auto/button.rs
@@ -334,6 +334,7 @@ impl ButtonBuilder {
     /// Build the [`Button`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Button {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/calendar.rs b/gtk4/src/auto/calendar.rs
index 9cc2e8dfa482..e7d5da2bd56a 100644
--- a/gtk4/src/auto/calendar.rs
+++ b/gtk4/src/auto/calendar.rs
@@ -685,6 +685,7 @@ impl CalendarBuilder {
     /// Build the [`Calendar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Calendar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_area_box.rs b/gtk4/src/auto/cell_area_box.rs
index 19c04a20b76b..d469a3af4c95 100644
--- a/gtk4/src/auto/cell_area_box.rs
+++ b/gtk4/src/auto/cell_area_box.rs
@@ -167,6 +167,7 @@ impl CellAreaBoxBuilder {
     /// Build the [`CellAreaBox`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellAreaBox {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_accel.rs b/gtk4/src/auto/cell_renderer_accel.rs
index 6216c6c8f066..2e54165a612a 100644
--- a/gtk4/src/auto/cell_renderer_accel.rs
+++ b/gtk4/src/auto/cell_renderer_accel.rs
@@ -656,6 +656,7 @@ impl CellRendererAccelBuilder {
     /// Build the [`CellRendererAccel`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererAccel {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_combo.rs b/gtk4/src/auto/cell_renderer_combo.rs
index ae86eacdbcec..7c342ce5749f 100644
--- a/gtk4/src/auto/cell_renderer_combo.rs
+++ b/gtk4/src/auto/cell_renderer_combo.rs
@@ -581,6 +581,7 @@ impl CellRendererComboBuilder {
     /// Build the [`CellRendererCombo`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererCombo {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_pixbuf.rs b/gtk4/src/auto/cell_renderer_pixbuf.rs
index dafc806b89e2..72d64a63a0ec 100644
--- a/gtk4/src/auto/cell_renderer_pixbuf.rs
+++ b/gtk4/src/auto/cell_renderer_pixbuf.rs
@@ -431,6 +431,7 @@ impl CellRendererPixbufBuilder {
     /// Build the [`CellRendererPixbuf`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererPixbuf {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_progress.rs b/gtk4/src/auto/cell_renderer_progress.rs
index f1cc549d7842..5856eb62ccc9 100644
--- a/gtk4/src/auto/cell_renderer_progress.rs
+++ b/gtk4/src/auto/cell_renderer_progress.rs
@@ -390,6 +390,7 @@ impl CellRendererProgressBuilder {
     /// Build the [`CellRendererProgress`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererProgress {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_spin.rs b/gtk4/src/auto/cell_renderer_spin.rs
index 5dcf4835cb5b..28aa055b830d 100644
--- a/gtk4/src/auto/cell_renderer_spin.rs
+++ b/gtk4/src/auto/cell_renderer_spin.rs
@@ -551,6 +551,7 @@ impl CellRendererSpinBuilder {
     /// Build the [`CellRendererSpin`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererSpin {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_spinner.rs b/gtk4/src/auto/cell_renderer_spinner.rs
index 5dc9abf8ba6e..5c444389d761 100644
--- a/gtk4/src/auto/cell_renderer_spinner.rs
+++ b/gtk4/src/auto/cell_renderer_spinner.rs
@@ -265,6 +265,7 @@ impl CellRendererSpinnerBuilder {
     /// Build the [`CellRendererSpinner`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererSpinner {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_text.rs b/gtk4/src/auto/cell_renderer_text.rs
index 33c1e12344d8..077aa4d4dc0e 100644
--- a/gtk4/src/auto/cell_renderer_text.rs
+++ b/gtk4/src/auto/cell_renderer_text.rs
@@ -438,6 +438,7 @@ impl CellRendererTextBuilder {
     /// Build the [`CellRendererText`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererText {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_renderer_toggle.rs b/gtk4/src/auto/cell_renderer_toggle.rs
index f41739c876a2..46a5b4590d32 100644
--- a/gtk4/src/auto/cell_renderer_toggle.rs
+++ b/gtk4/src/auto/cell_renderer_toggle.rs
@@ -376,6 +376,7 @@ impl CellRendererToggleBuilder {
     /// Build the [`CellRendererToggle`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellRendererToggle {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/cell_view.rs b/gtk4/src/auto/cell_view.rs
index 587c131fcb2b..db1f31c50d53 100644
--- a/gtk4/src/auto/cell_view.rs
+++ b/gtk4/src/auto/cell_view.rs
@@ -509,6 +509,7 @@ impl CellViewBuilder {
     /// Build the [`CellView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CellView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/center_box.rs b/gtk4/src/auto/center_box.rs
index ad832d00cec9..ef16e6ce7b5d 100644
--- a/gtk4/src/auto/center_box.rs
+++ b/gtk4/src/auto/center_box.rs
@@ -530,6 +530,7 @@ impl CenterBoxBuilder {
     /// Build the [`CenterBox`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CenterBox {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/check_button.rs b/gtk4/src/auto/check_button.rs
index 12b5f42bc13f..7e140079b089 100644
--- a/gtk4/src/auto/check_button.rs
+++ b/gtk4/src/auto/check_button.rs
@@ -324,6 +324,7 @@ impl CheckButtonBuilder {
     /// Build the [`CheckButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> CheckButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/color_button.rs b/gtk4/src/auto/color_button.rs
index 4495aa85fb71..8ea9abc610a5 100644
--- a/gtk4/src/auto/color_button.rs
+++ b/gtk4/src/auto/color_button.rs
@@ -461,6 +461,7 @@ impl ColorButtonBuilder {
     /// Build the [`ColorButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColorButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/color_chooser_dialog.rs b/gtk4/src/auto/color_chooser_dialog.rs
index b214f1603f48..c6e2cf0e8d39 100644
--- a/gtk4/src/auto/color_chooser_dialog.rs
+++ b/gtk4/src/auto/color_chooser_dialog.rs
@@ -473,6 +473,7 @@ impl ColorChooserDialogBuilder {
     /// Build the [`ColorChooserDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColorChooserDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/color_chooser_widget.rs b/gtk4/src/auto/color_chooser_widget.rs
index c21e9d653053..028ef7bd4265 100644
--- a/gtk4/src/auto/color_chooser_widget.rs
+++ b/gtk4/src/auto/color_chooser_widget.rs
@@ -301,6 +301,7 @@ impl ColorChooserWidgetBuilder {
     /// Build the [`ColorChooserWidget`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColorChooserWidget {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/color_dialog.rs b/gtk4/src/auto/color_dialog.rs
index 348d2ec1df6b..2b21100d92aa 100644
--- a/gtk4/src/auto/color_dialog.rs
+++ b/gtk4/src/auto/color_dialog.rs
@@ -278,6 +278,7 @@ impl ColorDialogBuilder {
     /// Build the [`ColorDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColorDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/color_dialog_button.rs b/gtk4/src/auto/color_dialog_button.rs
index 35a94623e2d9..7b1cf711d36e 100644
--- a/gtk4/src/auto/color_dialog_button.rs
+++ b/gtk4/src/auto/color_dialog_button.rs
@@ -381,6 +381,7 @@ impl ColorDialogButtonBuilder {
     /// Build the [`ColorDialogButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColorDialogButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/column_view.rs b/gtk4/src/auto/column_view.rs
index 480e906d0f7f..e67c22cdca04 100644
--- a/gtk4/src/auto/column_view.rs
+++ b/gtk4/src/auto/column_view.rs
@@ -911,6 +911,7 @@ impl ColumnViewBuilder {
     /// Build the [`ColumnView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColumnView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/column_view_cell.rs b/gtk4/src/auto/column_view_cell.rs
index 02df8a0f8dde..171a23f6b24e 100644
--- a/gtk4/src/auto/column_view_cell.rs
+++ b/gtk4/src/auto/column_view_cell.rs
@@ -155,6 +155,7 @@ impl ColumnViewCellBuilder {
     /// Build the [`ColumnViewCell`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColumnViewCell {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/column_view_column.rs b/gtk4/src/auto/column_view_column.rs
index 602f31bec4de..776af7488fc5 100644
--- a/gtk4/src/auto/column_view_column.rs
+++ b/gtk4/src/auto/column_view_column.rs
@@ -538,6 +538,7 @@ impl ColumnViewColumnBuilder {
     /// Build the [`ColumnViewColumn`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColumnViewColumn {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/column_view_row.rs b/gtk4/src/auto/column_view_row.rs
index 7f5a04da2b30..079e18258df9 100644
--- a/gtk4/src/auto/column_view_row.rs
+++ b/gtk4/src/auto/column_view_row.rs
@@ -421,6 +421,7 @@ impl ColumnViewRowBuilder {
     /// Build the [`ColumnViewRow`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ColumnViewRow {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/combo_box.rs b/gtk4/src/auto/combo_box.rs
index 29b55accfccd..5bfa58cbe86a 100644
--- a/gtk4/src/auto/combo_box.rs
+++ b/gtk4/src/auto/combo_box.rs
@@ -362,6 +362,7 @@ impl ComboBoxBuilder {
     /// Build the [`ComboBox`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ComboBox {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/combo_box_text.rs b/gtk4/src/auto/combo_box_text.rs
index 01a0f5d76f2d..24518434292b 100644
--- a/gtk4/src/auto/combo_box_text.rs
+++ b/gtk4/src/auto/combo_box_text.rs
@@ -428,6 +428,7 @@ impl ComboBoxTextBuilder {
     /// Build the [`ComboBoxText`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ComboBoxText {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/constraint.rs b/gtk4/src/auto/constraint.rs
index 1208edbaf4b3..01a09defbfa1 100644
--- a/gtk4/src/auto/constraint.rs
+++ b/gtk4/src/auto/constraint.rs
@@ -217,6 +217,7 @@ impl ConstraintBuilder {
     /// Build the [`Constraint`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Constraint {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/constraint_guide.rs b/gtk4/src/auto/constraint_guide.rs
index a83fa43c3059..daffd9afc6a6 100644
--- a/gtk4/src/auto/constraint_guide.rs
+++ b/gtk4/src/auto/constraint_guide.rs
@@ -406,6 +406,7 @@ impl ConstraintGuideBuilder {
     /// Build the [`ConstraintGuide`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ConstraintGuide {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/dialog.rs b/gtk4/src/auto/dialog.rs
index 5682401e54e2..4cd533b70aef 100644
--- a/gtk4/src/auto/dialog.rs
+++ b/gtk4/src/auto/dialog.rs
@@ -417,6 +417,7 @@ impl DialogBuilder {
     /// Build the [`Dialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Dialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/drag_source.rs b/gtk4/src/auto/drag_source.rs
index 86c44738c8a4..94ecf49afc4c 100644
--- a/gtk4/src/auto/drag_source.rs
+++ b/gtk4/src/auto/drag_source.rs
@@ -340,6 +340,7 @@ impl DragSourceBuilder {
     /// Build the [`DragSource`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> DragSource {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/drawing_area.rs b/gtk4/src/auto/drawing_area.rs
index a14f6036c26c..dc4ee14c1f14 100644
--- a/gtk4/src/auto/drawing_area.rs
+++ b/gtk4/src/auto/drawing_area.rs
@@ -262,6 +262,7 @@ impl DrawingAreaBuilder {
     /// Build the [`DrawingArea`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> DrawingArea {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/drop_controller_motion.rs b/gtk4/src/auto/drop_controller_motion.rs
index 0e9ae6e24cdb..e671c141188a 100644
--- a/gtk4/src/auto/drop_controller_motion.rs
+++ b/gtk4/src/auto/drop_controller_motion.rs
@@ -258,6 +258,7 @@ impl DropControllerMotionBuilder {
     /// Build the [`DropControllerMotion`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> DropControllerMotion {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/drop_down.rs b/gtk4/src/auto/drop_down.rs
index 5b951e911d90..debb2eddcf8b 100644
--- a/gtk4/src/auto/drop_down.rs
+++ b/gtk4/src/auto/drop_down.rs
@@ -783,6 +783,7 @@ impl DropDownBuilder {
     /// Build the [`DropDown`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> DropDown {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/drop_target.rs b/gtk4/src/auto/drop_target.rs
index dfc6e56c5b0e..1605b2679543 100644
--- a/gtk4/src/auto/drop_target.rs
+++ b/gtk4/src/auto/drop_target.rs
@@ -396,6 +396,7 @@ impl DropTargetBuilder {
     /// Build the [`DropTarget`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> DropTarget {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/drop_target_async.rs b/gtk4/src/auto/drop_target_async.rs
index f8af68b2d9d8..4660b2ac6a75 100644
--- a/gtk4/src/auto/drop_target_async.rs
+++ b/gtk4/src/auto/drop_target_async.rs
@@ -332,6 +332,7 @@ impl DropTargetAsyncBuilder {
     /// Build the [`DropTargetAsync`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> DropTargetAsync {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/editable_label.rs b/gtk4/src/auto/editable_label.rs
index b8a5bf10af68..0cbcef56c0f0 100644
--- a/gtk4/src/auto/editable_label.rs
+++ b/gtk4/src/auto/editable_label.rs
@@ -316,6 +316,7 @@ impl EditableLabelBuilder {
     /// Build the [`EditableLabel`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EditableLabel {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/emoji_chooser.rs b/gtk4/src/auto/emoji_chooser.rs
index c7419c2fcbc0..c8a8243d93e4 100644
--- a/gtk4/src/auto/emoji_chooser.rs
+++ b/gtk4/src/auto/emoji_chooser.rs
@@ -326,6 +326,7 @@ impl EmojiChooserBuilder {
     /// Build the [`EmojiChooser`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EmojiChooser {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/entry.rs b/gtk4/src/auto/entry.rs
index 28b29dc34689..f35b149edbec 100644
--- a/gtk4/src/auto/entry.rs
+++ b/gtk4/src/auto/entry.rs
@@ -583,6 +583,7 @@ impl EntryBuilder {
     /// Build the [`Entry`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Entry {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/entry_buffer.rs b/gtk4/src/auto/entry_buffer.rs
index 7cc461ace2d6..6a689467ec48 100644
--- a/gtk4/src/auto/entry_buffer.rs
+++ b/gtk4/src/auto/entry_buffer.rs
@@ -63,6 +63,7 @@ impl EntryBufferBuilder {
     /// Build the [`EntryBuffer`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EntryBuffer {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/entry_completion.rs b/gtk4/src/auto/entry_completion.rs
index 771ce9e97855..0a23ff711915 100644
--- a/gtk4/src/auto/entry_completion.rs
+++ b/gtk4/src/auto/entry_completion.rs
@@ -748,6 +748,7 @@ impl EntryCompletionBuilder {
     /// Build the [`EntryCompletion`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EntryCompletion {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/event_controller_focus.rs b/gtk4/src/auto/event_controller_focus.rs
index 5aa919db236f..4d86b8a9a7b9 100644
--- a/gtk4/src/auto/event_controller_focus.rs
+++ b/gtk4/src/auto/event_controller_focus.rs
@@ -197,6 +197,7 @@ impl EventControllerFocusBuilder {
     /// Build the [`EventControllerFocus`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EventControllerFocus {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/event_controller_key.rs b/gtk4/src/auto/event_controller_key.rs
index 194f5e057b8e..d6c2e38dcc10 100644
--- a/gtk4/src/auto/event_controller_key.rs
+++ b/gtk4/src/auto/event_controller_key.rs
@@ -171,6 +171,7 @@ impl EventControllerKeyBuilder {
     /// Build the [`EventControllerKey`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EventControllerKey {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/event_controller_legacy.rs b/gtk4/src/auto/event_controller_legacy.rs
index a95e351b22f0..2578d4d67ffb 100644
--- a/gtk4/src/auto/event_controller_legacy.rs
+++ b/gtk4/src/auto/event_controller_legacy.rs
@@ -113,6 +113,7 @@ impl EventControllerLegacyBuilder {
     /// Build the [`EventControllerLegacy`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EventControllerLegacy {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/event_controller_motion.rs b/gtk4/src/auto/event_controller_motion.rs
index 927a52254490..ff38cc5804c0 100644
--- a/gtk4/src/auto/event_controller_motion.rs
+++ b/gtk4/src/auto/event_controller_motion.rs
@@ -227,6 +227,7 @@ impl EventControllerMotionBuilder {
     /// Build the [`EventControllerMotion`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EventControllerMotion {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/event_controller_scroll.rs b/gtk4/src/auto/event_controller_scroll.rs
index c9d7bd8aba1c..1019fec80dcb 100644
--- a/gtk4/src/auto/event_controller_scroll.rs
+++ b/gtk4/src/auto/event_controller_scroll.rs
@@ -244,6 +244,7 @@ impl EventControllerScrollBuilder {
     /// Build the [`EventControllerScroll`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> EventControllerScroll {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/expander.rs b/gtk4/src/auto/expander.rs
index 102cfa11fd13..d820ad69780f 100644
--- a/gtk4/src/auto/expander.rs
+++ b/gtk4/src/auto/expander.rs
@@ -603,6 +603,7 @@ impl ExpanderBuilder {
     /// Build the [`Expander`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Expander {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/file_chooser_dialog.rs b/gtk4/src/auto/file_chooser_dialog.rs
index 1b116e15d465..f8e17d75242d 100644
--- a/gtk4/src/auto/file_chooser_dialog.rs
+++ b/gtk4/src/auto/file_chooser_dialog.rs
@@ -424,6 +424,7 @@ impl FileChooserDialogBuilder {
     /// Build the [`FileChooserDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FileChooserDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/file_chooser_native.rs b/gtk4/src/auto/file_chooser_native.rs
index 364f463b4db2..ae96b81c3143 100644
--- a/gtk4/src/auto/file_chooser_native.rs
+++ b/gtk4/src/auto/file_chooser_native.rs
@@ -242,6 +242,7 @@ impl FileChooserNativeBuilder {
     /// Build the [`FileChooserNative`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FileChooserNative {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/file_chooser_widget.rs b/gtk4/src/auto/file_chooser_widget.rs
index e88351de4130..71aec3ed0a21 100644
--- a/gtk4/src/auto/file_chooser_widget.rs
+++ b/gtk4/src/auto/file_chooser_widget.rs
@@ -703,6 +703,7 @@ impl FileChooserWidgetBuilder {
     /// Build the [`FileChooserWidget`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FileChooserWidget {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/file_dialog.rs b/gtk4/src/auto/file_dialog.rs
index 298379da1973..644e88fb25fd 100644
--- a/gtk4/src/auto/file_dialog.rs
+++ b/gtk4/src/auto/file_dialog.rs
@@ -815,6 +815,7 @@ impl FileDialogBuilder {
     /// Build the [`FileDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FileDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/filter_list_model.rs b/gtk4/src/auto/filter_list_model.rs
index 4cb81ba161c0..1c99888971e2 100644
--- a/gtk4/src/auto/filter_list_model.rs
+++ b/gtk4/src/auto/filter_list_model.rs
@@ -256,6 +256,7 @@ impl FilterListModelBuilder {
     /// Build the [`FilterListModel`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FilterListModel {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/fixed.rs b/gtk4/src/auto/fixed.rs
index cc66ab361a24..dda22bb3bdfd 100644
--- a/gtk4/src/auto/fixed.rs
+++ b/gtk4/src/auto/fixed.rs
@@ -245,6 +245,7 @@ impl FixedBuilder {
     /// Build the [`Fixed`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Fixed {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/flow_box.rs b/gtk4/src/auto/flow_box.rs
index 4a91036ed5b7..c97d8c61da24 100644
--- a/gtk4/src/auto/flow_box.rs
+++ b/gtk4/src/auto/flow_box.rs
@@ -1067,6 +1067,7 @@ impl FlowBoxBuilder {
     /// Build the [`FlowBox`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FlowBox {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/flow_box_child.rs b/gtk4/src/auto/flow_box_child.rs
index 0d612d65425c..00254447d3c7 100644
--- a/gtk4/src/auto/flow_box_child.rs
+++ b/gtk4/src/auto/flow_box_child.rs
@@ -256,6 +256,7 @@ impl FlowBoxChildBuilder {
     /// Build the [`FlowBoxChild`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FlowBoxChild {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/font_button.rs b/gtk4/src/auto/font_button.rs
index 91293daee158..d9e15d4c57f4 100644
--- a/gtk4/src/auto/font_button.rs
+++ b/gtk4/src/auto/font_button.rs
@@ -552,6 +552,7 @@ impl FontButtonBuilder {
     /// Build the [`FontButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FontButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/font_chooser_dialog.rs b/gtk4/src/auto/font_chooser_dialog.rs
index 3a97d64e22dc..8b8952000881 100644
--- a/gtk4/src/auto/font_chooser_dialog.rs
+++ b/gtk4/src/auto/font_chooser_dialog.rs
@@ -460,6 +460,7 @@ impl FontChooserDialogBuilder {
     /// Build the [`FontChooserDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FontChooserDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/font_chooser_widget.rs b/gtk4/src/auto/font_chooser_widget.rs
index ace2919c4ce2..b3676506a355 100644
--- a/gtk4/src/auto/font_chooser_widget.rs
+++ b/gtk4/src/auto/font_chooser_widget.rs
@@ -323,6 +323,7 @@ impl FontChooserWidgetBuilder {
     /// Build the [`FontChooserWidget`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FontChooserWidget {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/font_dialog.rs b/gtk4/src/auto/font_dialog.rs
index 75e94d9df698..2b24e8cf1ab8 100644
--- a/gtk4/src/auto/font_dialog.rs
+++ b/gtk4/src/auto/font_dialog.rs
@@ -534,6 +534,7 @@ impl FontDialogBuilder {
     /// Build the [`FontDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FontDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/font_dialog_button.rs b/gtk4/src/auto/font_dialog_button.rs
index bba33c941a9f..3f2fab378661 100644
--- a/gtk4/src/auto/font_dialog_button.rs
+++ b/gtk4/src/auto/font_dialog_button.rs
@@ -677,6 +677,7 @@ impl FontDialogButtonBuilder {
     /// Build the [`FontDialogButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> FontDialogButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/frame.rs b/gtk4/src/auto/frame.rs
index 8333a8d3676a..194fdc61cc1e 100644
--- a/gtk4/src/auto/frame.rs
+++ b/gtk4/src/auto/frame.rs
@@ -276,6 +276,7 @@ impl FrameBuilder {
     /// Build the [`Frame`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Frame {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_click.rs b/gtk4/src/auto/gesture_click.rs
index 93d7dbabcbb2..58aa2367b276 100644
--- a/gtk4/src/auto/gesture_click.rs
+++ b/gtk4/src/auto/gesture_click.rs
@@ -220,6 +220,7 @@ impl GestureClickBuilder {
     /// Build the [`GestureClick`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureClick {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_drag.rs b/gtk4/src/auto/gesture_drag.rs
index ef514cbc95c8..a7cb943d1c4a 100644
--- a/gtk4/src/auto/gesture_drag.rs
+++ b/gtk4/src/auto/gesture_drag.rs
@@ -109,6 +109,7 @@ impl GestureDragBuilder {
     /// Build the [`GestureDrag`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureDrag {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_long_press.rs b/gtk4/src/auto/gesture_long_press.rs
index 8a3a23fa9aa7..db998b55a93a 100644
--- a/gtk4/src/auto/gesture_long_press.rs
+++ b/gtk4/src/auto/gesture_long_press.rs
@@ -197,6 +197,7 @@ impl GestureLongPressBuilder {
     /// Build the [`GestureLongPress`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureLongPress {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_pan.rs b/gtk4/src/auto/gesture_pan.rs
index e1793b9ae974..144afa97a631 100644
--- a/gtk4/src/auto/gesture_pan.rs
+++ b/gtk4/src/auto/gesture_pan.rs
@@ -179,6 +179,7 @@ impl GesturePanBuilder {
     /// Build the [`GesturePan`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GesturePan {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_rotate.rs b/gtk4/src/auto/gesture_rotate.rs
index 98d7d2a95115..52d77a62e064 100644
--- a/gtk4/src/auto/gesture_rotate.rs
+++ b/gtk4/src/auto/gesture_rotate.rs
@@ -119,6 +119,7 @@ impl GestureRotateBuilder {
     /// Build the [`GestureRotate`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureRotate {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_stylus.rs b/gtk4/src/auto/gesture_stylus.rs
index c29219affa6b..b00822d0b13e 100644
--- a/gtk4/src/auto/gesture_stylus.rs
+++ b/gtk4/src/auto/gesture_stylus.rs
@@ -309,6 +309,7 @@ impl GestureStylusBuilder {
     /// Build the [`GestureStylus`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureStylus {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_swipe.rs b/gtk4/src/auto/gesture_swipe.rs
index a19fbbf47a99..8842a5faa5a0 100644
--- a/gtk4/src/auto/gesture_swipe.rs
+++ b/gtk4/src/auto/gesture_swipe.rs
@@ -150,6 +150,7 @@ impl GestureSwipeBuilder {
     /// Build the [`GestureSwipe`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureSwipe {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gesture_zoom.rs b/gtk4/src/auto/gesture_zoom.rs
index 90c82f49279a..a74396ff87c4 100644
--- a/gtk4/src/auto/gesture_zoom.rs
+++ b/gtk4/src/auto/gesture_zoom.rs
@@ -118,6 +118,7 @@ impl GestureZoomBuilder {
     /// Build the [`GestureZoom`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GestureZoom {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/gl_area.rs b/gtk4/src/auto/gl_area.rs
index 35f0e956f9ec..8c3043bccc7b 100644
--- a/gtk4/src/auto/gl_area.rs
+++ b/gtk4/src/auto/gl_area.rs
@@ -286,6 +286,7 @@ impl GLAreaBuilder {
     /// Build the [`GLArea`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GLArea {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/graphics_offload.rs b/gtk4/src/auto/graphics_offload.rs
index 0560b024c49e..a12ceaf8dea2 100644
--- a/gtk4/src/auto/graphics_offload.rs
+++ b/gtk4/src/auto/graphics_offload.rs
@@ -413,6 +413,7 @@ impl GraphicsOffloadBuilder {
     /// Build the [`GraphicsOffload`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GraphicsOffload {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/grid.rs b/gtk4/src/auto/grid.rs
index 48fc9485fcb4..80da49d04b3b 100644
--- a/gtk4/src/auto/grid.rs
+++ b/gtk4/src/auto/grid.rs
@@ -288,6 +288,7 @@ impl GridBuilder {
     /// Build the [`Grid`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Grid {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/grid_layout.rs b/gtk4/src/auto/grid_layout.rs
index 215553fe8b1d..d056b70c1729 100644
--- a/gtk4/src/auto/grid_layout.rs
+++ b/gtk4/src/auto/grid_layout.rs
@@ -322,6 +322,7 @@ impl GridLayoutBuilder {
     /// Build the [`GridLayout`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GridLayout {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/grid_view.rs b/gtk4/src/auto/grid_view.rs
index ec75777098e2..9dc3cce36d67 100644
--- a/gtk4/src/auto/grid_view.rs
+++ b/gtk4/src/auto/grid_view.rs
@@ -676,6 +676,7 @@ impl GridViewBuilder {
     /// Build the [`GridView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> GridView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/header_bar.rs b/gtk4/src/auto/header_bar.rs
index 9f0b4a129bec..1e7c217cdff0 100644
--- a/gtk4/src/auto/header_bar.rs
+++ b/gtk4/src/auto/header_bar.rs
@@ -427,6 +427,7 @@ impl HeaderBarBuilder {
     /// Build the [`HeaderBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> HeaderBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/icon_theme.rs b/gtk4/src/auto/icon_theme.rs
index 945ded713e52..c2107da5a19e 100644
--- a/gtk4/src/auto/icon_theme.rs
+++ b/gtk4/src/auto/icon_theme.rs
@@ -390,6 +390,7 @@ impl IconThemeBuilder {
     /// Build the [`IconTheme`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> IconTheme {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/icon_view.rs b/gtk4/src/auto/icon_view.rs
index b441813819e3..336237e56b36 100644
--- a/gtk4/src/auto/icon_view.rs
+++ b/gtk4/src/auto/icon_view.rs
@@ -1786,6 +1786,7 @@ impl IconViewBuilder {
     /// Build the [`IconView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> IconView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/im_context_simple.rs b/gtk4/src/auto/im_context_simple.rs
index 53a4b1d49015..5b8fa3076c47 100644
--- a/gtk4/src/auto/im_context_simple.rs
+++ b/gtk4/src/auto/im_context_simple.rs
@@ -70,6 +70,7 @@ impl IMContextSimpleBuilder {
     /// Build the [`IMContextSimple`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> IMContextSimple {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/im_multicontext.rs b/gtk4/src/auto/im_multicontext.rs
index 46b5efcb3358..d57bf4a7ee72 100644
--- a/gtk4/src/auto/im_multicontext.rs
+++ b/gtk4/src/auto/im_multicontext.rs
@@ -70,6 +70,7 @@ impl IMMulticontextBuilder {
     /// Build the [`IMMulticontext`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> IMMulticontext {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/image.rs b/gtk4/src/auto/image.rs
index 537fd048daec..9900c36b63e8 100644
--- a/gtk4/src/auto/image.rs
+++ b/gtk4/src/auto/image.rs
@@ -717,6 +717,7 @@ impl ImageBuilder {
     /// Build the [`Image`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Image {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/info_bar.rs b/gtk4/src/auto/info_bar.rs
index b6a6455d1968..e9dcee89ccf4 100644
--- a/gtk4/src/auto/info_bar.rs
+++ b/gtk4/src/auto/info_bar.rs
@@ -540,6 +540,7 @@ impl InfoBarBuilder {
     /// Build the [`InfoBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> InfoBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/inscription.rs b/gtk4/src/auto/inscription.rs
index 5dd92d9c6f9d..4c5599d21b63 100644
--- a/gtk4/src/auto/inscription.rs
+++ b/gtk4/src/auto/inscription.rs
@@ -788,6 +788,7 @@ impl InscriptionBuilder {
     /// Build the [`Inscription`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Inscription {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/label.rs b/gtk4/src/auto/label.rs
index c9380ee2070d..cb69d63576dd 100644
--- a/gtk4/src/auto/label.rs
+++ b/gtk4/src/auto/label.rs
@@ -1371,6 +1371,7 @@ impl LabelBuilder {
     /// Build the [`Label`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Label {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/level_bar.rs b/gtk4/src/auto/level_bar.rs
index 27fcab7f8b4e..a8cba9af79c7 100644
--- a/gtk4/src/auto/level_bar.rs
+++ b/gtk4/src/auto/level_bar.rs
@@ -567,6 +567,7 @@ impl LevelBarBuilder {
     /// Build the [`LevelBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> LevelBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/link_button.rs b/gtk4/src/auto/link_button.rs
index 740e7feeeae0..4e76b094771d 100644
--- a/gtk4/src/auto/link_button.rs
+++ b/gtk4/src/auto/link_button.rs
@@ -429,6 +429,7 @@ impl LinkButtonBuilder {
     /// Build the [`LinkButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> LinkButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/list_box.rs b/gtk4/src/auto/list_box.rs
index f314fad99995..cf3c41abb01c 100644
--- a/gtk4/src/auto/list_box.rs
+++ b/gtk4/src/auto/list_box.rs
@@ -1016,6 +1016,7 @@ impl ListBoxBuilder {
     /// Build the [`ListBox`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ListBox {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/list_box_row.rs b/gtk4/src/auto/list_box_row.rs
index 8d48021d1110..6834724e0e90 100644
--- a/gtk4/src/auto/list_box_row.rs
+++ b/gtk4/src/auto/list_box_row.rs
@@ -282,6 +282,7 @@ impl ListBoxRowBuilder {
     /// Build the [`ListBoxRow`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ListBoxRow {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/list_view.rs b/gtk4/src/auto/list_view.rs
index 8af43fd1a264..9246ee3ba726 100644
--- a/gtk4/src/auto/list_view.rs
+++ b/gtk4/src/auto/list_view.rs
@@ -696,6 +696,7 @@ impl ListViewBuilder {
     /// Build the [`ListView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ListView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/lock_button.rs b/gtk4/src/auto/lock_button.rs
index aeaad66c24ff..70011ec3aebc 100644
--- a/gtk4/src/auto/lock_button.rs
+++ b/gtk4/src/auto/lock_button.rs
@@ -586,6 +586,7 @@ impl LockButtonBuilder {
     /// Build the [`LockButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> LockButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/media_controls.rs b/gtk4/src/auto/media_controls.rs
index 576827beb600..7e3ea43e9993 100644
--- a/gtk4/src/auto/media_controls.rs
+++ b/gtk4/src/auto/media_controls.rs
@@ -306,6 +306,7 @@ impl MediaControlsBuilder {
     /// Build the [`MediaControls`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> MediaControls {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/menu_button.rs b/gtk4/src/auto/menu_button.rs
index 2e1035358551..afe5269323b3 100644
--- a/gtk4/src/auto/menu_button.rs
+++ b/gtk4/src/auto/menu_button.rs
@@ -915,6 +915,7 @@ impl MenuButtonBuilder {
     /// Build the [`MenuButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> MenuButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/message_dialog.rs b/gtk4/src/auto/message_dialog.rs
index 818fc6f22592..d83977c0797e 100644
--- a/gtk4/src/auto/message_dialog.rs
+++ b/gtk4/src/auto/message_dialog.rs
@@ -653,6 +653,7 @@ impl MessageDialogBuilder {
     /// Build the [`MessageDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> MessageDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/mount_operation.rs b/gtk4/src/auto/mount_operation.rs
index 80adf5b21235..38a66afc53bb 100644
--- a/gtk4/src/auto/mount_operation.rs
+++ b/gtk4/src/auto/mount_operation.rs
@@ -138,6 +138,7 @@ impl MountOperationBuilder {
     /// Build the [`MountOperation`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> MountOperation {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/notebook.rs b/gtk4/src/auto/notebook.rs
index 052ebecdc860..0fd688535990 100644
--- a/gtk4/src/auto/notebook.rs
+++ b/gtk4/src/auto/notebook.rs
@@ -1067,6 +1067,7 @@ impl NotebookBuilder {
     /// Build the [`Notebook`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Notebook {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/numeric_sorter.rs b/gtk4/src/auto/numeric_sorter.rs
index 9b663c946415..b0190a613f03 100644
--- a/gtk4/src/auto/numeric_sorter.rs
+++ b/gtk4/src/auto/numeric_sorter.rs
@@ -167,6 +167,7 @@ impl NumericSorterBuilder {
     /// Build the [`NumericSorter`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> NumericSorter {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/overlay.rs b/gtk4/src/auto/overlay.rs
index 15685bc85e9c..c2a057f5749e 100644
--- a/gtk4/src/auto/overlay.rs
+++ b/gtk4/src/auto/overlay.rs
@@ -355,6 +355,7 @@ impl OverlayBuilder {
     /// Build the [`Overlay`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Overlay {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/pad_controller.rs b/gtk4/src/auto/pad_controller.rs
index 506ed18f7d5a..a73275a3e0c8 100644
--- a/gtk4/src/auto/pad_controller.rs
+++ b/gtk4/src/auto/pad_controller.rs
@@ -141,6 +141,7 @@ impl PadControllerBuilder {
     /// Build the [`PadController`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PadController {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/page_setup_unix_dialog.rs b/gtk4/src/auto/page_setup_unix_dialog.rs
index e53a96d0b060..a22debb272a1 100644
--- a/gtk4/src/auto/page_setup_unix_dialog.rs
+++ b/gtk4/src/auto/page_setup_unix_dialog.rs
@@ -453,6 +453,7 @@ impl PageSetupUnixDialogBuilder {
     /// Build the [`PageSetupUnixDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PageSetupUnixDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/paned.rs b/gtk4/src/auto/paned.rs
index 43050eb38ae6..4efee5e3ae51 100644
--- a/gtk4/src/auto/paned.rs
+++ b/gtk4/src/auto/paned.rs
@@ -903,6 +903,7 @@ impl PanedBuilder {
     /// Build the [`Paned`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Paned {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/password_entry.rs b/gtk4/src/auto/password_entry.rs
index 2b752da0de96..33082e74f84a 100644
--- a/gtk4/src/auto/password_entry.rs
+++ b/gtk4/src/auto/password_entry.rs
@@ -501,6 +501,7 @@ impl PasswordEntryBuilder {
     /// Build the [`PasswordEntry`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PasswordEntry {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/password_entry_buffer.rs b/gtk4/src/auto/password_entry_buffer.rs
index e3f11e27c3a6..e84fa4ca0aad 100644
--- a/gtk4/src/auto/password_entry_buffer.rs
+++ b/gtk4/src/auto/password_entry_buffer.rs
@@ -68,6 +68,7 @@ impl PasswordEntryBufferBuilder {
     /// Build the [`PasswordEntryBuffer`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PasswordEntryBuffer {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/picture.rs b/gtk4/src/auto/picture.rs
index 5795e2a6c028..2ae7ef213617 100644
--- a/gtk4/src/auto/picture.rs
+++ b/gtk4/src/auto/picture.rs
@@ -639,6 +639,7 @@ impl PictureBuilder {
     /// Build the [`Picture`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Picture {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/popover.rs b/gtk4/src/auto/popover.rs
index 73f7cb33b68b..068676daaf90 100644
--- a/gtk4/src/auto/popover.rs
+++ b/gtk4/src/auto/popover.rs
@@ -302,6 +302,7 @@ impl PopoverBuilder {
     /// Build the [`Popover`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Popover {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/popover_menu.rs b/gtk4/src/auto/popover_menu.rs
index 9d79921bf819..2831235325ce 100644
--- a/gtk4/src/auto/popover_menu.rs
+++ b/gtk4/src/auto/popover_menu.rs
@@ -478,6 +478,7 @@ impl PopoverMenuBuilder {
     /// Build the [`PopoverMenu`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PopoverMenu {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/popover_menu_bar.rs b/gtk4/src/auto/popover_menu_bar.rs
index 4eef4467bc31..95d43e4e484a 100644
--- a/gtk4/src/auto/popover_menu_bar.rs
+++ b/gtk4/src/auto/popover_menu_bar.rs
@@ -322,6 +322,7 @@ impl PopoverMenuBarBuilder {
     /// Build the [`PopoverMenuBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PopoverMenuBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/print_dialog.rs b/gtk4/src/auto/print_dialog.rs
index e8829721d721..f50955b66e47 100644
--- a/gtk4/src/auto/print_dialog.rs
+++ b/gtk4/src/auto/print_dialog.rs
@@ -535,6 +535,7 @@ impl PrintDialogBuilder {
     /// Build the [`PrintDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PrintDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/print_operation.rs b/gtk4/src/auto/print_operation.rs
index 48c2f1e1f8aa..9c29a0420d08 100644
--- a/gtk4/src/auto/print_operation.rs
+++ b/gtk4/src/auto/print_operation.rs
@@ -168,6 +168,7 @@ impl PrintOperationBuilder {
     /// Build the [`PrintOperation`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PrintOperation {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/print_unix_dialog.rs b/gtk4/src/auto/print_unix_dialog.rs
index 125b1ef9a2d7..cf65c39d4737 100644
--- a/gtk4/src/auto/print_unix_dialog.rs
+++ b/gtk4/src/auto/print_unix_dialog.rs
@@ -843,6 +843,7 @@ impl PrintUnixDialogBuilder {
     /// Build the [`PrintUnixDialog`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> PrintUnixDialog {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/progress_bar.rs b/gtk4/src/auto/progress_bar.rs
index b97d06cde4da..81fa2d733e6b 100644
--- a/gtk4/src/auto/progress_bar.rs
+++ b/gtk4/src/auto/progress_bar.rs
@@ -537,6 +537,7 @@ impl ProgressBarBuilder {
     /// Build the [`ProgressBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ProgressBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/revealer.rs b/gtk4/src/auto/revealer.rs
index 6765e6148b05..8ae6a815cad9 100644
--- a/gtk4/src/auto/revealer.rs
+++ b/gtk4/src/auto/revealer.rs
@@ -461,6 +461,7 @@ impl RevealerBuilder {
     /// Build the [`Revealer`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Revealer {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/scale.rs b/gtk4/src/auto/scale.rs
index 0467a3f62fa3..54fdf044c7c5 100644
--- a/gtk4/src/auto/scale.rs
+++ b/gtk4/src/auto/scale.rs
@@ -356,6 +356,7 @@ impl ScaleBuilder {
     /// Build the [`Scale`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Scale {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/scale_button.rs b/gtk4/src/auto/scale_button.rs
index 497f6b1e17d6..7aa484b65c69 100644
--- a/gtk4/src/auto/scale_button.rs
+++ b/gtk4/src/auto/scale_button.rs
@@ -307,6 +307,7 @@ impl ScaleButtonBuilder {
     /// Build the [`ScaleButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ScaleButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/scrollbar.rs b/gtk4/src/auto/scrollbar.rs
index 4d682fdfd166..9ed2a1ea5f6a 100644
--- a/gtk4/src/auto/scrollbar.rs
+++ b/gtk4/src/auto/scrollbar.rs
@@ -323,6 +323,7 @@ impl ScrollbarBuilder {
     /// Build the [`Scrollbar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Scrollbar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/scrolled_window.rs b/gtk4/src/auto/scrolled_window.rs
index a7cfb2b98fb8..4c78f687fc6c 100644
--- a/gtk4/src/auto/scrolled_window.rs
+++ b/gtk4/src/auto/scrolled_window.rs
@@ -1209,6 +1209,7 @@ impl ScrolledWindowBuilder {
     /// Build the [`ScrolledWindow`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ScrolledWindow {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/search_bar.rs b/gtk4/src/auto/search_bar.rs
index fc3444c0f4df..6651886ca537 100644
--- a/gtk4/src/auto/search_bar.rs
+++ b/gtk4/src/auto/search_bar.rs
@@ -462,6 +462,7 @@ impl SearchBarBuilder {
     /// Build the [`SearchBar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> SearchBar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/search_entry.rs b/gtk4/src/auto/search_entry.rs
index 33b4398a8e74..9b353e4201a0 100644
--- a/gtk4/src/auto/search_entry.rs
+++ b/gtk4/src/auto/search_entry.rs
@@ -700,6 +700,7 @@ impl SearchEntryBuilder {
     /// Build the [`SearchEntry`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> SearchEntry {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/separator.rs b/gtk4/src/auto/separator.rs
index 151e9ac512da..4b2ba6261061 100644
--- a/gtk4/src/auto/separator.rs
+++ b/gtk4/src/auto/separator.rs
@@ -251,6 +251,7 @@ impl SeparatorBuilder {
     /// Build the [`Separator`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Separator {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/settings.rs b/gtk4/src/auto/settings.rs
index c2a1cfde0f77..73731cd1e916 100644
--- a/gtk4/src/auto/settings.rs
+++ b/gtk4/src/auto/settings.rs
@@ -2445,6 +2445,7 @@ impl SettingsBuilder {
     /// Build the [`Settings`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Settings {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/shortcut.rs b/gtk4/src/auto/shortcut.rs
index d61a337e0ca6..557daf2e185f 100644
--- a/gtk4/src/auto/shortcut.rs
+++ b/gtk4/src/auto/shortcut.rs
@@ -204,6 +204,7 @@ impl ShortcutBuilder {
     /// Build the [`Shortcut`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Shortcut {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/shortcut_label.rs b/gtk4/src/auto/shortcut_label.rs
index 304bedd2d0cc..aada08f35b15 100644
--- a/gtk4/src/auto/shortcut_label.rs
+++ b/gtk4/src/auto/shortcut_label.rs
@@ -352,6 +352,7 @@ impl ShortcutLabelBuilder {
     /// Build the [`ShortcutLabel`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ShortcutLabel {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/shortcuts_group.rs b/gtk4/src/auto/shortcuts_group.rs
index 61a0c6f20ad6..35bb06b8f6ed 100644
--- a/gtk4/src/auto/shortcuts_group.rs
+++ b/gtk4/src/auto/shortcuts_group.rs
@@ -459,6 +459,7 @@ impl ShortcutsGroupBuilder {
     /// Build the [`ShortcutsGroup`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ShortcutsGroup {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/shortcuts_section.rs b/gtk4/src/auto/shortcuts_section.rs
index be4efbb9d8b7..475a97a34bd7 100644
--- a/gtk4/src/auto/shortcuts_section.rs
+++ b/gtk4/src/auto/shortcuts_section.rs
@@ -436,6 +436,7 @@ impl ShortcutsSectionBuilder {
     /// Build the [`ShortcutsSection`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ShortcutsSection {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/shortcuts_shortcut.rs b/gtk4/src/auto/shortcuts_shortcut.rs
index cfa9a805f899..7196bce20334 100644
--- a/gtk4/src/auto/shortcuts_shortcut.rs
+++ b/gtk4/src/auto/shortcuts_shortcut.rs
@@ -637,6 +637,7 @@ impl ShortcutsShortcutBuilder {
     /// Build the [`ShortcutsShortcut`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ShortcutsShortcut {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/shortcuts_window.rs b/gtk4/src/auto/shortcuts_window.rs
index 7a47c6671e55..716de80eeaa2 100644
--- a/gtk4/src/auto/shortcuts_window.rs
+++ b/gtk4/src/auto/shortcuts_window.rs
@@ -534,6 +534,7 @@ impl ShortcutsWindowBuilder {
     /// Build the [`ShortcutsWindow`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ShortcutsWindow {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/single_selection.rs b/gtk4/src/auto/single_selection.rs
index 5a614155aeb0..3e7d633ba961 100644
--- a/gtk4/src/auto/single_selection.rs
+++ b/gtk4/src/auto/single_selection.rs
@@ -302,6 +302,7 @@ impl SingleSelectionBuilder {
     /// Build the [`SingleSelection`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> SingleSelection {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/slice_list_model.rs b/gtk4/src/auto/slice_list_model.rs
index b4ab7c2f9da5..42a96b6f9143 100644
--- a/gtk4/src/auto/slice_list_model.rs
+++ b/gtk4/src/auto/slice_list_model.rs
@@ -214,6 +214,7 @@ impl SliceListModelBuilder {
     /// Build the [`SliceListModel`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> SliceListModel {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/sort_list_model.rs b/gtk4/src/auto/sort_list_model.rs
index a7be84d761e3..55a4ea38e114 100644
--- a/gtk4/src/auto/sort_list_model.rs
+++ b/gtk4/src/auto/sort_list_model.rs
@@ -317,6 +317,7 @@ impl SortListModelBuilder {
     /// Build the [`SortListModel`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> SortListModel {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/spin_button.rs b/gtk4/src/auto/spin_button.rs
index 0a4205a76087..8251a2caee58 100644
--- a/gtk4/src/auto/spin_button.rs
+++ b/gtk4/src/auto/spin_button.rs
@@ -974,6 +974,7 @@ impl SpinButtonBuilder {
     /// Build the [`SpinButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> SpinButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/spinner.rs b/gtk4/src/auto/spinner.rs
index bb6b1e3d268b..36820a9764b1 100644
--- a/gtk4/src/auto/spinner.rs
+++ b/gtk4/src/auto/spinner.rs
@@ -306,6 +306,7 @@ impl SpinnerBuilder {
     /// Build the [`Spinner`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Spinner {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/stack.rs b/gtk4/src/auto/stack.rs
index de9fb1cd3150..029d7d6f73a3 100644
--- a/gtk4/src/auto/stack.rs
+++ b/gtk4/src/auto/stack.rs
@@ -714,6 +714,7 @@ impl StackBuilder {
     /// Build the [`Stack`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Stack {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/stack_sidebar.rs b/gtk4/src/auto/stack_sidebar.rs
index 44d09395d3bc..c11464b85250 100644
--- a/gtk4/src/auto/stack_sidebar.rs
+++ b/gtk4/src/auto/stack_sidebar.rs
@@ -291,6 +291,7 @@ impl StackSidebarBuilder {
     /// Build the [`StackSidebar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> StackSidebar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/stack_switcher.rs b/gtk4/src/auto/stack_switcher.rs
index 4b809c42aac5..753a7fec0175 100644
--- a/gtk4/src/auto/stack_switcher.rs
+++ b/gtk4/src/auto/stack_switcher.rs
@@ -297,6 +297,7 @@ impl StackSwitcherBuilder {
     /// Build the [`StackSwitcher`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> StackSwitcher {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/statusbar.rs b/gtk4/src/auto/statusbar.rs
index 2af594cf7dec..1213a24a2942 100644
--- a/gtk4/src/auto/statusbar.rs
+++ b/gtk4/src/auto/statusbar.rs
@@ -356,6 +356,7 @@ impl StatusbarBuilder {
     /// Build the [`Statusbar`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Statusbar {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/string_filter.rs b/gtk4/src/auto/string_filter.rs
index 49f478dd1d9d..b9e67e008d3c 100644
--- a/gtk4/src/auto/string_filter.rs
+++ b/gtk4/src/auto/string_filter.rs
@@ -250,6 +250,7 @@ impl StringFilterBuilder {
     /// Build the [`StringFilter`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> StringFilter {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/string_sorter.rs b/gtk4/src/auto/string_sorter.rs
index 0f260fea8f6c..68fe5b616376 100644
--- a/gtk4/src/auto/string_sorter.rs
+++ b/gtk4/src/auto/string_sorter.rs
@@ -217,6 +217,7 @@ impl StringSorterBuilder {
     /// Build the [`StringSorter`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> StringSorter {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/switch.rs b/gtk4/src/auto/switch.rs
index ce0e3a479482..75dac6580831 100644
--- a/gtk4/src/auto/switch.rs
+++ b/gtk4/src/auto/switch.rs
@@ -403,6 +403,7 @@ impl SwitchBuilder {
     /// Build the [`Switch`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Switch {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/text.rs b/gtk4/src/auto/text.rs
index 3b9dce223ba3..9447d22e0d54 100644
--- a/gtk4/src/auto/text.rs
+++ b/gtk4/src/auto/text.rs
@@ -1160,6 +1160,7 @@ impl TextBuilder {
     /// Build the [`Text`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Text {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/text_buffer.rs b/gtk4/src/auto/text_buffer.rs
index 5a5d4510a19b..d7b46d5cb5ef 100644
--- a/gtk4/src/auto/text_buffer.rs
+++ b/gtk4/src/auto/text_buffer.rs
@@ -81,6 +81,7 @@ impl TextBufferBuilder {
     /// Build the [`TextBuffer`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TextBuffer {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/text_mark.rs b/gtk4/src/auto/text_mark.rs
index 0b5a51cf08ba..8f6f4c1f5fbf 100644
--- a/gtk4/src/auto/text_mark.rs
+++ b/gtk4/src/auto/text_mark.rs
@@ -75,6 +75,7 @@ impl TextMarkBuilder {
     /// Build the [`TextMark`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TextMark {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/text_tag.rs b/gtk4/src/auto/text_tag.rs
index 53043b176a9d..ec263ce61d9d 100644
--- a/gtk4/src/auto/text_tag.rs
+++ b/gtk4/src/auto/text_tag.rs
@@ -657,6 +657,7 @@ impl TextTagBuilder {
     /// Build the [`TextTag`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TextTag {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/text_view.rs b/gtk4/src/auto/text_view.rs
index b63a1940446c..0c059efbaaa7 100644
--- a/gtk4/src/auto/text_view.rs
+++ b/gtk4/src/auto/text_view.rs
@@ -441,6 +441,7 @@ impl TextViewBuilder {
     /// Build the [`TextView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TextView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/toggle_button.rs b/gtk4/src/auto/toggle_button.rs
index e86903175a1a..2e6e37f8a484 100644
--- a/gtk4/src/auto/toggle_button.rs
+++ b/gtk4/src/auto/toggle_button.rs
@@ -339,6 +339,7 @@ impl ToggleButtonBuilder {
     /// Build the [`ToggleButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> ToggleButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/tree_expander.rs b/gtk4/src/auto/tree_expander.rs
index 4f8c9edd4bce..9f2875707e03 100644
--- a/gtk4/src/auto/tree_expander.rs
+++ b/gtk4/src/auto/tree_expander.rs
@@ -544,6 +544,7 @@ impl TreeExpanderBuilder {
     /// Build the [`TreeExpander`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TreeExpander {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/tree_view.rs b/gtk4/src/auto/tree_view.rs
index 497205f15aca..9ac065f28eac 100644
--- a/gtk4/src/auto/tree_view.rs
+++ b/gtk4/src/auto/tree_view.rs
@@ -413,6 +413,7 @@ impl TreeViewBuilder {
     /// Build the [`TreeView`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TreeView {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/tree_view_column.rs b/gtk4/src/auto/tree_view_column.rs
index ed940dd6cc82..9f0aca1d6fbf 100644
--- a/gtk4/src/auto/tree_view_column.rs
+++ b/gtk4/src/auto/tree_view_column.rs
@@ -1212,6 +1212,7 @@ impl TreeViewColumnBuilder {
     /// Build the [`TreeViewColumn`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> TreeViewColumn {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/uri_launcher.rs b/gtk4/src/auto/uri_launcher.rs
index 2accaa22436b..c828fafc0667 100644
--- a/gtk4/src/auto/uri_launcher.rs
+++ b/gtk4/src/auto/uri_launcher.rs
@@ -174,6 +174,7 @@ impl UriLauncherBuilder {
     /// Build the [`UriLauncher`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> UriLauncher {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/versions.txt b/gtk4/src/auto/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gtk4/src/auto/versions.txt
+++ b/gtk4/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)
diff --git a/gtk4/src/auto/video.rs b/gtk4/src/auto/video.rs
index 6172c781496b..81c2b783b2a4 100644
--- a/gtk4/src/auto/video.rs
+++ b/gtk4/src/auto/video.rs
@@ -551,6 +551,7 @@ impl VideoBuilder {
     /// Build the [`Video`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Video {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/viewport.rs b/gtk4/src/auto/viewport.rs
index 886e8f7f2bad..9cccb0e0d6fa 100644
--- a/gtk4/src/auto/viewport.rs
+++ b/gtk4/src/auto/viewport.rs
@@ -394,6 +394,7 @@ impl ViewportBuilder {
     /// Build the [`Viewport`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Viewport {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/volume_button.rs b/gtk4/src/auto/volume_button.rs
index 488325e9164b..5d96feccd0bb 100644
--- a/gtk4/src/auto/volume_button.rs
+++ b/gtk4/src/auto/volume_button.rs
@@ -343,6 +343,7 @@ impl VolumeButtonBuilder {
     /// Build the [`VolumeButton`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> VolumeButton {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/window.rs b/gtk4/src/auto/window.rs
index 4786698646ac..93eb66320ad6 100644
--- a/gtk4/src/auto/window.rs
+++ b/gtk4/src/auto/window.rs
@@ -451,6 +451,7 @@ impl WindowBuilder {
     /// Build the [`Window`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> Window {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/window_controls.rs b/gtk4/src/auto/window_controls.rs
index a3db7f4eda8a..81c6082997b3 100644
--- a/gtk4/src/auto/window_controls.rs
+++ b/gtk4/src/auto/window_controls.rs
@@ -381,6 +381,7 @@ impl WindowControlsBuilder {
     /// Build the [`WindowControls`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> WindowControls {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/src/auto/window_handle.rs b/gtk4/src/auto/window_handle.rs
index 16a80a4c299e..27793f11c48e 100644
--- a/gtk4/src/auto/window_handle.rs
+++ b/gtk4/src/auto/window_handle.rs
@@ -294,6 +294,7 @@ impl WindowHandleBuilder {
     /// Build the [`WindowHandle`].
     #[must_use = "Building the object from the builder is usually expensive and is not expected to have side effects"]
     pub fn build(self) -> WindowHandle {
+        assert_initialized_main_thread!();
         self.builder.build()
     }
 }
diff --git a/gtk4/sys/versions.txt b/gtk4/sys/versions.txt
index 60ae865ee3d0..21e0e3409dca 100644
--- a/gtk4/sys/versions.txt
+++ b/gtk4/sys/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ af6703cf6545)
-from gir-files (https://github.com/gtk-rs/gir-files @ e45712216c81)
+Generated by gir (https://github.com/gtk-rs/gir @ d7ce1bd186a7)
+from gir-files (https://github.com/gtk-rs/gir-files @ f7af0e711383)