This class creates a stand-alone menu button. It does not need
to be added to a menuBar. CMenuBotton looks like a button (Fig.1) but
works like a menu. When the button is pressed, a pull down menu will
appear (Fig.2).
Like awt.Menu, any menuItem, separator and subclass of menuItem such as
JavaMenuItem and ShellMenuItem
can be added to this widget.
To distinguish from a normal awt.Button, a ">>" String is added on back
of the label set by the user. If the label is not set, the
default label ">>" will appear on the CMenuBotton.
Fig. 1 A CMenuButton
Fig. 2 A pressed CButton