pyGTK warning

[alexrait1]

Hello,
GtkWarning: gtk_widget_grab_default: assertion `GTK_WIDGET_CAN_DEFAULT
(widget)' failed

I am using python gtk binding with glade.

All I did was to create a gui interface with glade (Stored as xml) and
to load it with
gtk.glade.XML("filename.glade");
Then I run it with gkt.main() and got this warning..
what can it possible be, since google seems not to know about it.
thanx.