code: public void showPanel(AbstractPanel panel) {
  		validateNotNull(panel, "panel");
  
  		if (layout == Layout.FULL) {
  			getTabbedFull().setVisible(panel, true);
  		} else {
  			getTabbedSelect().setVisible(panel, true);
  			getTabbedStatus().setVisible(panel, true);
  			getTabbedWork().setVisible(panel, true);
  		}
  		panel.setTabFocus();
  	}
docs: Shows the given panel, if it was previously added.
  <p>
  It does nothing, if the tab is already shown.
  
  @param panel the panel to be shown
  @throws IllegalArgumentException if the given parameter is {@code null}.
  @since 2.5.0
  @see #addPanel(AbstractPanel, PanelType)