added default 'Flag' also to visibility op

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2644 5a81b35b-ba03-0410-adc8-b2c5c5119f08

modules/gui/pymod/scene/visibility_op.py

@@ -66,7 +66,9 @@ class VisibilityOp():
     visible_op = None
     if group.HasAttribute(VisibilityOp.VISIBLE_ATTRIBUTE_NAME):
       visible = bool(int(group.GetAttribute(VisibilityOp.VISIBLE_ATTRIBUTE_NAME)))
-      flags = int(group.GetAttribute(VisibilityOp.FLAGS_ATTRIBUTE_NAME))
+      flags = 0
+      if group.HasAttribute(VisibilityOp.FLAGS_ATTRIBUTE_NAME):
+        flags = int(group.GetAttribute(VisibilityOp.FLAGS_ATTRIBUTE_NAME))
       selection = group.GetTextData()
       visible_op = VisibilityOp(selection,flags,visible)
     return visible_op