/**
* generate new element for panel
* @param panel
*/
public JButton addButton(UserPanel panel){
ActionListener al = new ActivatePanelAction(panel, container);
JButton button = new JButton();
button.addActionListener(al);
button.setIcon(panel.getIcon());
button.setToolTipText(panel.getDescription());
ToolbarElement element = new ToolbarElement(panel, al, button);