diff --git a/modules/gui/pymod/dng/superpositiondialog.py b/modules/gui/pymod/dng/superpositiondialog.py
index 12a405994ee4c7288b5f664c7abbef5f000d587a..2112ce2cd97e12fe828c53bd3d3e10be23c5ad26 100644
--- a/modules/gui/pymod/dng/superpositiondialog.py
+++ b/modules/gui/pymod/dng/superpositiondialog.py
@@ -40,6 +40,8 @@ class ChainComboBox(QComboBox):
       QObject.connect(self,
                       SIGNAL('highlighted (const QString&)'),
                       self._HighlightChain)
+    else:
+      self.gfx = None
 
   def focusOutEvent (self, event):
     if self.gfx:
@@ -113,7 +115,8 @@ class SuperpositionDialog(QDialog):
     else:
       scene.CenterOn(g2)
 
-    LogScript('RMSD: %.3f'%sd.rmsd)
+    if sd.rmsd != None:
+      LogScript('RMSD: %.3f'%sd.rmsd)
   """
 
   def __init__(self, ent_one, ent_two, parent=None):