@Test
public void testLinkPanelInitalNull() {

    if (GraphicsEnvironment.isHeadless()) {
        LOG.fine("cannot run testLinkPanelNull - headless");
        return;
    }
    JXDatePicker picker = new JXDatePicker();
    picker.setLinkPanel(null);
    JXFrame frame = new JXFrame("showing", false);
    frame.add(picker);
    frame.setVisible(true);
    Action togglePopup = picker.getActionMap().get("TOGGLE_POPUP");
    togglePopup.actionPerformed(null);
    frame.dispose();
}