Hi Louis,
Too frustrated to offer proofed WD source .. (WEBDEV)
Try this :
RECT is structure
left is int
top is int
right is int
bottom is int
END
hwnd is int = Handle(YOUR_WINDEV_CONTROL)
lpRect is RECT
r is boolean = API("USER32", "GetClientRect", hWnd, &lpRect)
// bla, bla, bla
// lpRect contains the data (right/left) you need to calculate the width
all I can do atm.Bjoern