Give some flicker - but you got the titlebarheight.
Winni
Couldn't this then be simply done by using a new form, give it an alpha value of 0 and doing all the stuff with it? this would at least not be visible.
Also, while not being a big problem, you should also consider than in linux one can change the style easily during runtime, meaning the size during one moment might not be the same size at another time