private void updateDefaultMouseHandler() {
            // UI has changed. Only BasicTableHeaderUI can be handled here.
            for (MouseListener l : tableHeader.getMouseListeners()) {
                if (l instanceof MouseInputHandler) {
                    tableHeader.removeMouseListener(l);
                    defaultMouseHandler = l;
                    return;
                }
            }
            // For non BasicTableHeaderUI, just use an empty handler.
            defaultMouseHandler = EMPTY_MOUSE_HAMDLER;
        }