Backport from develbranch_6 of bug fix for scalebar properties setting

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32834 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gui_modules/gdialogs.py

@@ -327,6 +327,9 @@ class DecorationDialog(wx.Dialog):
                                                            'coords': (10, 10),
                                                            'pdcType': 'image' }
         else:
+            if self.parent.MapWindow.overlays[self.ovlId]['propwin'] == None:
+                return
+
             self.parent.MapWindow.overlays[self.ovlId]['propwin'].get_dcmd = self.GetOptData