diff --git a/src/value/map.rs b/src/value/map.rs
index 2c100c024..fd840caa4 100644
--- a/src/value/map.rs
+++ b/src/value/map.rs
@@ -62,7 +62,14 @@ impl Map {
 
     /// Removes an element by its `key`.
     pub fn remove(&mut self, key: &Value) -> Option<Value> {
-        self.0.remove(key)
+        #[cfg(feature = "indexmap")]
+        {
+            self.0.shift_remove(key)
+        }
+        #[cfg(not(feature = "indexmap"))]
+        {
+            self.0.remove(key)
+        }
     }
 
     /// Iterate all key-value pairs.
diff --git a/tests/526_flatten.rs b/tests/526_flatten.rs
new file mode 100644
index 000000000..7bc56168b
--- /dev/null
+++ b/tests/526_flatten.rs
@@ -0,0 +1,54 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct SomeCollection {
+    inner: Vec<SomeItem>,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct SomeItem {
+    #[serde(flatten)]
+    foo: Foo,
+    #[serde(flatten)]
+    bar: Bar,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct Bar {
+    name: String,
+    some_enum: Option<SomeEnum>,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct Foo {
+    something: String,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+enum SomeEnum {
+    A,
+    B,
+}
+
+#[test]
+fn roundtrip() {
+    let scene = SomeCollection {
+        inner: vec![SomeItem {
+            foo: Foo {
+                something: "something".to_string(),
+            },
+            bar: Bar {
+                name: "name".to_string(),
+                some_enum: Some(SomeEnum::A),
+            },
+        }],
+    };
+
+    let ron = ron::ser::to_string(&scene).unwrap();
+    let de: SomeCollection = ron::de::from_str(&ron).unwrap();
+    assert_eq!(de, scene);
+
+    let ron = ron::ser::to_string_pretty(&scene, Default::default()).unwrap();
+    let _deser_scene: SomeCollection = ron::de::from_str(&ron).unwrap();
+    assert_eq!(de, scene);
+}