Int 2F Fn 4006  C - Windows 3.x - Switching Dos To Foreground              [W]

   AX = 4006h

Note:  called by Windows when the DOS box is about to be placed in the
     foreground and the video driver should restore any necessary state
     information (this may be called only in Standard mode)

See Also: AX=4002h,AX=4005h