INT 16 U - PCIBM PC Tools v5.1-8.0 DESKTOP - DISPLAY POPUP MENU
	AX = FFDEh
	DS:DX -> menu description (must be on a paragraph boundary)
Return: AX = ???
	    AL seems to be the number of the selected button
Note:	available only when popped up
SeeAlso: AX=FFEEh