NAME
	OnMenu -- Enable the given menu or menu item.
    SYNOPSIS
	OnMenu( Window, MenuNumber )
	        A0      D0
	VOID OnMenu( struct Window *, UWORD );
    FUNCTION
	This command enables a sub-item, an item, or a whole menu.
	This depends on the contents of the data packed into MenuNumber,
	which is described in the Intuition Reference Manual.
    INPUTS
	Window = pointer to the window
	MenuNumber = the menu piece to be enables
    RESULT
	None
    BUGS
    SEE ALSO
	OffMenu(), ResetMenuStrip()