--- a/controls/VariablePanel.py	Mon Apr 23 11:16:40 2012 +0200
+++ b/controls/VariablePanel.py	Fri Apr 27 01:55:45 2012 +0200
@@ -551,19 +551,20 @@
         setattr(self.VariablesGrid, "_MoveRow", _MoveVariable)
         
         def _RefreshButtons():
-            table_length = len(self.Table.data)
-            row_class = None
-            row_edit = True
-            row = 0
-            if table_length > 0:
-                row = self.VariablesGrid.GetGridCursorRow()
-                row_edit = self.Table.GetValueByName(row, "Edit")
-                if self.PouIsUsed:
-                    row_class = self.Table.GetValueByName(row, "Class")
-            self.AddButton.Enable(not self.Debug and (not self.PouIsUsed or self.Filter not in ["Interface", "Input", "Output", "InOut"]))
-            self.DeleteButton.Enable(not self.Debug and (table_length > 0 and row_edit and row_class not in ["Input", "Output", "InOut"]))
-            self.UpButton.Enable(not self.Debug and (table_length > 0 and row > 0 and self.Filter == "All" and row_class not in ["Input", "Output", "InOut"]))
-            self.DownButton.Enable(not self.Debug and (table_length > 0 and row < table_length - 1 and self.Filter == "All" and row_class not in ["Input", "Output", "InOut"]))
+            if self:
+                table_length = len(self.Table.data)
+                row_class = None
+                row_edit = True
+                row = 0
+                if table_length > 0:
+                    row = self.VariablesGrid.GetGridCursorRow()
+                    row_edit = self.Table.GetValueByName(row, "Edit")
+                    if self.PouIsUsed:
+                        row_class = self.Table.GetValueByName(row, "Class")
+                self.AddButton.Enable(not self.Debug and (not self.PouIsUsed or self.Filter not in ["Interface", "Input", "Output", "InOut"]))
+                self.DeleteButton.Enable(not self.Debug and (table_length > 0 and row_edit and row_class not in ["Input", "Output", "InOut"]))
+                self.UpButton.Enable(not self.Debug and (table_length > 0 and row > 0 and self.Filter == "All" and row_class not in ["Input", "Output", "InOut"]))
+                self.DownButton.Enable(not self.Debug and (table_length > 0 and row < table_length - 1 and self.Filter == "All" and row_class not in ["Input", "Output", "InOut"]))
         setattr(self.VariablesGrid, "RefreshButtons", _RefreshButtons)
         
         self.VariablesGrid.SetRowLabelSize(0)