The following widgets do not have an associated window. If you want to
capture events, you'll have to use the EventBox. See the section on
the EventBox widget.
| GtkAlignment
GtkArrow
GtkBin
GtkBox
GtkButton
GtkCheckButton
GtkFixed
GtkImage
GtkLabel
GtkMenuItem
GtkNotebook
GtkPaned
GtkRadioButton
GtkRange
GtkScrolledWindow
GtkSeparator
GtkTable
GtkToolbar
GtkAspectFrame
GtkFrame
GtkVBox
GtkHBox
GtkVSeparator
GtkHSeparator | 
We'll further our exploration of GTK by examining each widget in turn,
creating a few simple functions to display them. Another good source
is the testgtk program that comes with GTK. It can be found in
tests/testgtk.c.