This may happen if the window is destroyed at just the right moment.
return;
rects = XShapeGetRectangles(compositor->display, window->window, ShapeBounding, &rect_count, &rect_order);
return;
rects = XShapeGetRectangles(compositor->display, window->window, ShapeBounding, &rect_count, &rect_order);
width = window->width+2*window->border;
height = window->height+2*window->border;
width = window->width+2*window->border;
height = window->height+2*window->border;