public void mouseUp(MouseEvent event) {
		if (event.button != 1) {
			resetSession(); // abort if right or middle mouse button pressed
			return;
		}
		if (! dragInProgress) return; // spurious event
		dragInProgress = false;
		if (anchorPosition.x == -1) return; // spurious event
		
		getPaintSurface().commitRubberbandSelection();
	}