INT 2F - MS Windows 3.1 - SET FOCUS TO SPECIFIED VIRTUAL MACHINE                
	AX = 168Bh
	BX = virtual machine ID (see AX=1683h), 0000h for current DOS box
Return: AL = 00h if focus set to specified VMsee Virtual Machine
Notes:	documented on the Microsoft Developer's Network CD-ROM
	if the VMsee Virtual Machine is a windowed DOS box, it will be set to full screen
SeeAlso: AX=1683h