Returns the #GtkApplicationWindow with the given ID.
The ID of a #GtkApplicationWindow can be retrieved with gtk_application_window_get_id().
an identifier number
the window with ID @id, or %NULL if there is no window with this ID
3.6
See Implementation
Returns the #GtkApplicationWindow with the given ID.
The ID of a #GtkApplicationWindow can be retrieved with gtk_application_window_get_id().