Comment out code in MouseMove, MouseUp and change MouseDown to

LPARAMETERS nButton, nShift, nXCoord, nYCoord
IF nButton = 1
	ReleaseCapture()
	SendMessage(_VFP.HWnd, 0x112, 0xF012, 0x0)
ENDIF

>Thanks! That got me on the right track.
>
>Problem: The app moves smoothly, except there is some kind of strange refresh
>going on which persists after I release the mouse. See this:
>http://marois-consulting.com/stuff/image1.jpg
>
>My project is here if your interested. Run Test.prg
>http://marois-consulting.com/stuff/proj.zip
>
>