If I understand you correctly you are trying to determine the client area available for the main VFP desktop window. To my knowledge there are no direct properties that can just be referenced, however you can cheat a little by using a small, borderless form with a background colour that matches your desktop. You can now toggle the WindowState between 0 (Normal) and 2 (Maximised), when the form is maximised you can get at its height property which will reflect the true client area available.

do form testform name goForm

goForm.WindowState = 2
wait window alltrim(str(goForm.Height))

*!* Dock a toolbar or turn status bar off.
goForm.WindowState = 0
goForm.WindowState = 2
wait window alltrim(str(goForm.Height))

Do not try and set the Visible property to .F., the form will have its WindowState updated correctly but does not change the Height or Width properties until the form becomes visible again. Also do not make the form an MDI form.

HTH
Neil