--- a/Viewer.py	Fri Jul 11 17:16:08 2008 +0200
+++ b/Viewer.py	Fri Jul 18 14:34:06 2008 +0200
@@ -528,13 +528,10 @@
                 self.loadInstance(instance, ids)
         self.RefreshScrollBars()
         
-        to_delete = []
         for wire in self.Wires:
             if not wire.IsConnectedCompatible():
-                to_delete.append(wire)
-        for wire in to_delete:
-            wire.Delete()
-    
+                wire.MarkAsInvalid()
+        
         self.Refresh(False)
     
     def GetMaxSize(self):