Window.setTitlebar

Sets a custom titlebar for window.

A typical widget used here is #GtkHeaderBar, as it provides various features expected of a titlebar while allowing the addition of child widgets to it.

If you set a custom titlebar, GTK+ will do its best to convince the window manager not to put its own titlebar on the window. Depending on the system, this function may not work for a window that is already visible, so you set the titlebar before calling [gtk.widget.Widget.show].