Fix a misbehavior of a conditional.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@541 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Form/Selection.py

@@ -158,7 +158,7 @@ class Selection(Acquisition.Implicit, Traversable, Persistent):
     def getSelectionCheckedUids(self):
         if not hasattr(self, 'selection_checked_uids'):
           self.selection_checked_uids = []
-        if self.selection_checked_uids is None:
+        elif self.selection_checked_uids is None:
           self.selection_checked_uids = []
         return self.selection_checked_uids