|  |  |  | GTK+ 3 Reference Manual |  | 
|---|---|---|---|---|
| Top | Description | Object Hierarchy | Implemented Interfaces | ||||
  GObject
   +----GInitiallyUnowned
         +----GtkWidget
               +----GtkContainer
                     +----GtkBin
                           +----GtkWindow
                           +----GtkAlignment
                           +----GtkComboBox
                           +----GtkFrame
                           +----GtkButton
                           +----GtkMenuItem
                           +----GtkEventBox
                           +----GtkExpander
                           +----GtkHandleBox
                           +----GtkToolItem
                           +----GtkOverlay
                           +----GtkScrolledWindow
                           +----GtkViewport
The GtkBin 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 GtkBin, including GtkWindow, GtkButton, GtkFrame, GtkHandleBox or GtkScrolledWindow.