If you run this example, it should help you understand the screen coordinate system and the window or client coordinate system being used. Move the cursor, and try to understand why the "x" and "y" values, (coordinates), change the way they do change. Press Esc to exit. #include <WinAPI.au3> Opt("MouseCoordMode", 1) ;1=absolute, 0=relative, 2=client HotKeySet("{ESC}", "Terminate") Local $exit = 1 While $exit Sleep(10) TtColXY() WEnd ; TtColXY() Tooltip shows colour, and cursor