Check for renWin before using it.

Author: David C. Lonie

Packages/vcs/Lib/VTKPlots.py

@@ -200,6 +200,9 @@ def leftButtonReleaseEvent(self, obj, event):
             self.clickRenderer = None
 
     def configureEvent(self, obj, ev):
+        if not self.renWin:
+            return
+
         cursor = self.renWin.GetCurrentCursor()
         if sys.platform == "darwin" and ev == "ModifiedEvent" and cursor != self.oldCursor:
             self.oldCursor = cursor