diff --git a/gui/response_design_view_widget.py b/gui/response_design_view_widget.py
index cfe7910..c76a2ca 100644
--- a/gui/response_design_view_widget.py
+++ b/gui/response_design_view_widget.py
@@ -148,7 +148,7 @@ def render_layer(self, layer):
     def set_extents_and_scalefactor(self, extent):
         with block_signals_to(self.canvas):
             self.canvas.setExtent(extent)
-            self.canvas.zoomByFactor(self.parent_view.scaleFactor.value())
+            self.canvas.zoomByFactor(round(self.parent_view.scaleFactor.value(), 1))
             if self.marker.marker:
                 self.marker.marker.updatePosition()
 
@@ -250,7 +250,11 @@ def canvas_changed(self):
         if self.is_active:
             from AcATaMa.gui.response_design_window import ResponseDesignWindow
             view_extent = self.render_widget.canvas.extent()
-            view_extent.scale(1/self.current_scale_factor)
+            try:
+                view_extent.scale(1/self.current_scale_factor)
+            except ZeroDivisionError:
+                self.current_scale_factor = self.scaleFactor.minimum()
+                view_extent.scale(1 / self.current_scale_factor)
 
             # set extent and scale factor for all view activated except this view
             for view_widget in ResponseDesignWindow.view_widgets:
@@ -262,7 +266,11 @@ def scalefactor_changed(self):
         # adjust view with the original extent (scale factor=1)
         # and with the new scale factor
         view_extent = self.render_widget.canvas.extent()
-        view_extent.scale(1 / self.current_scale_factor)
+        try:
+            view_extent.scale(1 / self.current_scale_factor)
+        except ZeroDivisionError:
+            self.current_scale_factor = self.scaleFactor.minimum()
+            view_extent.scale(1 / self.current_scale_factor)
         self.render_widget.set_extents_and_scalefactor(view_extent)
         # save the new scale factor
-        self.current_scale_factor = self.scaleFactor.value()
\ No newline at end of file
+        self.current_scale_factor = round(self.scaleFactor.value(), 1)
\ No newline at end of file
diff --git a/ui/response_design_view_widget.ui b/ui/response_design_view_widget.ui
index 6d18004..21809de 100644
--- a/ui/response_design_view_widget.ui
+++ b/ui/response_design_view_widget.ui
@@ -87,7 +87,7 @@
          <number>1</number>
         </property>
         <property name="minimum">
-         <double>0.000000000000000</double>
+         <double>0.100000000000000</double>
         </property>
         <property name="maximum">
          <double>1000.000000000000000</double>
@@ -95,6 +95,9 @@
         <property name="singleStep">
          <double>0.100000000000000</double>
         </property>
+        <property name="stepType">
+         <enum>QAbstractSpinBox::AdaptiveDecimalStepType</enum>
+        </property>
         <property name="value">
          <double>1.000000000000000</double>
         </property>