private void setupCentralPanel() {
    myCentralPanel.removeAll();
    if (myUsagePreviewPanel != null) {
      Disposer.dispose(myUsagePreviewPanel);
      myUsagePreviewPanel = null;
    }
    JScrollPane pane = ScrollPaneFactory.createScrollPane(myTree);

    if (UsageViewSettings.getInstance().IS_PREVIEW_USAGES) {
      Splitter splitter =
          new Splitter(false, UsageViewSettings.getInstance().PREVIEW_USAGES_SPLITTER_PROPORTIONS);
      pane.putClientProperty(UIUtil.KEEP_BORDER_SIDES, SideBorder.RIGHT);

      splitter.setFirstComponent(pane);
      myUsagePreviewPanel = new UsagePreviewPanel(myProject);
      myUsagePreviewPanel.setBorder(IdeBorderFactory.createBorder(SideBorder.LEFT));
      Disposer.register(this, myUsagePreviewPanel);
      splitter.setSecondComponent(myUsagePreviewPanel);
      myCentralPanel.add(splitter, BorderLayout.CENTER);
    } else {
      myCentralPanel.add(pane, BorderLayout.CENTER);
    }
    myCentralPanel.add(myButtonPanel, BorderLayout.SOUTH);

    myRootPanel.revalidate();
  }
  private void createActionsToolbar() {
    final JComponent leftActionsToolbar = createLeftActionsToolbar();
    final JComponent rightActionsToolbar = createRightActionsToolbar();

    JPanel westPanel = new JPanel(new BorderLayout());
    westPanel.add(leftActionsToolbar, BorderLayout.WEST);
    westPanel.add(rightActionsToolbar, BorderLayout.EAST);
    add(westPanel, BorderLayout.WEST);
  }