Skús to takto:
mouse_event(MOUSEEVENTF_LEFTDOWN, Pozice.X, Pozice.Y, 0, 0);
mouse_event(MOUSEEVENTF_LEFTUP, Pozice.X, Pozice.Y, 0, 0);
GetDoubleClickTime;
mouse_event(MOUSEEVENTF_LEFTDOWN, Pozice.X, PoziceY, 0, 0);
mouse_event(MOUSEEVENTF_LEFTUP, Pozice.X, Pozice.Y, 0, 0);