A widget that is not displayed on the screen.
The GtkInvisible widget is used internally in GTK+, and is probably not very useful for application developers.
It is used for reliable pointer grabs and selection handling in the code for drag-and-drop.
GtkInvisible ();-- Creates a new GtkInvisible.
-- Creates a new GtkInvisible object for a specified screen.
set_screen() Sets the GdkScreen where the invisible object will be displayed.