gtk-container, gtk-widget, gtk-buildable, g-object, common-lisp:standard-object, common-lisp:t

gtk-action-bar, gtk-alignment, gtk-button, gtk-combo-box, gtk-event-box, gtk-expander, gtk-flow-box-child, gtk-frame, gtk-handle-box, gtk-menu-item, gtk-overlay, gtk-popover, gtk-revealer, gtk-scrolled-window, gtk-search-bar, gtk-stack-sidebar, gtk-tool-item, gtk-viewport, gtk-window

The gtk-bin widget is a container with just one child. It is not very useful itself, but it is useful for deriving subclasses, since it provides common code needed for handling a single child widget.

Many GTK widgets are subclasses of the gtk-bin class, including the gtk-window, gtk-button, gtk-frame, or gtk-scrolled-window classes.