diff --git a/modules/gui/pymod/dng/superpositiondialog.py b/modules/gui/pymod/dng/superpositiondialog.py
index b0658c9fc1ff6d650be939a86383c4e86e65f3a3..4c22b4c9658ba7885bea4e30f2683eb8208c3404 100644
--- a/modules/gui/pymod/dng/superpositiondialog.py
+++ b/modules/gui/pymod/dng/superpositiondialog.py
@@ -41,6 +41,10 @@ class ChainComboBox(QComboBox):
                       SIGNAL('highlighted (const QString&)'),
                       self._HighlightChain)
 
+  def focusOutEvent (self, event):
+    if self.gfx:
+      self.gfx.SetSelection(self.entity.Select('cname=All'))
+
   def SetItems(self, ent, gfx):
     self.clear()
     self.entity = ent
@@ -76,9 +80,6 @@ class ChainComboBox(QComboBox):
         break
   selected_chain = property(_GetSelectedChain, _SetSelectedChain)
 
-  def focusOutEvent (self, event):
-    self.gfx.SetSelection(self.entity.Select('cname=All'))
-
 class SuperpositionDialog(QDialog):
   """
   Provides a graphical user interface to structurally superpose two entities.