Checks whether there is a #GdkScreen is associated with this widget. All toplevel widgets have an associated screen, and all widgets added into a hierarchy with a toplevel window at the top.
true if there is a #GdkScreen associated with the widget.
Checks whether there is a #GdkScreen is associated with this widget. All toplevel widgets have an associated screen, and all widgets added into a hierarchy with a toplevel window at the top.