I believe there is none working example of WM_MOUSELEAVE notification ( I could be wrong ), using TrackMouseEvent, on this Forum. I've had some serious trouble some time to make it work. I believe someone will use it one day :] Global $is_tracking = False Global $iteration = 1 ; Just to recognize different ConsoleWrite's in spammed console Global $hGui = GUICreate('') Global $sTrackMouseEvent = DllStructCreate('dword;dword;hwnd;dword') ; Creating TRACKMOUSEEVENT Structure Global $