Marks window as attached to attach_widget. This creates a logical binding
between the window and the widget it belongs to, which is used by GTK+ to
propagate information such as styling or accessibility to window as if it
was a children of attach_widget.
Examples of places where specifying this relation is useful are for instance
a GtkMenu created by a GtkComboBox, a completion popup window
created by GtkEntry or a typeahead search entry created by GtkTreeView.
Note that this function should not be confused with
gtk_window_set_transient_for(), which specifies a window manager relation
between two toplevels instead.
Passing NULL for attach_widget detaches the window.
Marks window as attached to attach_widget. This creates a logical binding between the window and the widget it belongs to, which is used by GTK+ to propagate information such as styling or accessibility to window as if it was a children of attach_widget. Examples of places where specifying this relation is useful are for instance a GtkMenu created by a GtkComboBox, a completion popup window created by GtkEntry or a typeahead search entry created by GtkTreeView. Note that this function should not be confused with gtk_window_set_transient_for(), which specifies a window manager relation between two toplevels instead. Passing NULL for attach_widget detaches the window.