Fixed warning triggered by gdk_window_get_type_hint notably for ooffice, by making sure that passed argument is indeed a GdkWindow.
Fixed warning triggered by gdk_window_get_type_hint notably for ooffice, by making sure that passed
argument is indeed a GdkWindow.

KDE/oxygen-gtk,blue-shell/carbon-gtk,blueshell-next/carbon-gtk,blue-shell/carbon-gtk,KDE/oxygen-gtk,blueshell-next/carbon-gtk