NO, ma qusta è una soluzione di peter hall:

codice:
onClipEvent (load) {
	width = 640;
	// stage width
	height = 400;
	// stage height
	/*  extrapolation parameter:
	* Low value (ie <1) = decrease chance of returning out when in
	* High value (ie >1) = decrease chance of returning in when out
	*/
	extrap = 1;
	//-------------------------------//
	pointerOut = false;
	x0;	x1;	y0;	y1;	dx;	dy;
}
onClipEvent (enterFrame) {
	x1 = _level0._xmouse;
	y1 = _level0._ymouse;
	if (x1 == x0 && y1 == y0) {
		// pointer movement not detected
		// extrapolate to find expected mouse pos and test for inside/outside
		if (x1 + extrap * dx < 0 || x1 + extrap * dx > width || y1 + extrap * dy < 0 || y1 + extrap * dy > height) {
			pointerOut = true;
		}
	} else {
		pointerOut = false;
		dx = x1 - x0;
		dy = y1 - y0;
		x0 = x1;
		y0 = y1;
	}
}
Poi puoi verificare la posizione tramite javascript, o tramite un pulsante sullo stage. 1000 modi, ma nessuno sicuro..