@Override
  protected JComponent createCenterPanel() {
    JPanel panel = new JPanel(new BorderLayout());

    // Toolbar

    DefaultActionGroup group = new DefaultActionGroup();

    fillToolbarActions(group);

    group.addSeparator();

    ExpandAllAction expandAllAction = new ExpandAllAction();
    expandAllAction.registerCustomShortcutSet(
        new CustomShortcutSet(
            KeymapManager.getInstance()
                .getActiveKeymap()
                .getShortcuts(IdeActions.ACTION_EXPAND_ALL)),
        myTree);
    group.add(expandAllAction);

    CollapseAllAction collapseAllAction = new CollapseAllAction();
    collapseAllAction.registerCustomShortcutSet(
        new CustomShortcutSet(
            KeymapManager.getInstance()
                .getActiveKeymap()
                .getShortcuts(IdeActions.ACTION_COLLAPSE_ALL)),
        myTree);
    group.add(collapseAllAction);

    panel.add(
        ActionManager.getInstance()
            .createActionToolbar(ActionPlaces.UNKNOWN, group, true)
            .getComponent(),
        BorderLayout.NORTH);

    // Tree
    expandFirst();
    defaultExpandTree();
    installSpeedSearch();

    JScrollPane scrollPane = ScrollPaneFactory.createScrollPane(myTree);
    scrollPane.setPreferredSize(new Dimension(350, 450));
    panel.add(scrollPane, BorderLayout.CENTER);

    return panel;
  }
  protected void fillToolbarActions(DefaultActionGroup group) {
    final boolean alphabeticallySorted = PropertiesComponent.getInstance().isTrueValue(PROP_SORTED);
    if (alphabeticallySorted) {
      setSortComparator(new OrderComparator());
    }
    myAlphabeticallySorted = alphabeticallySorted;
    group.add(mySortAction);

    if (!supportsNestedContainers()) {
      ShowContainersAction showContainersAction = getShowContainersAction();
      showContainersAction.registerCustomShortcutSet(
          new CustomShortcutSet(KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.ALT_MASK)),
          myTree);
      setShowClasses(PropertiesComponent.getInstance().isTrueValue(PROP_SHOWCLASSES));
      group.add(showContainersAction);
    }
  }