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

    if (isPreview()) {
      pane.setBorder(IdeBorderFactory.createBorder(SideBorder.LEFT | SideBorder.RIGHT));

      boolean vertical = myToolWindow.getAnchor() == ToolWindowAnchor.LEFT || myToolWindow.getAnchor() == ToolWindowAnchor.RIGHT;
      Splitter splitter = new Splitter(vertical, UsageViewSettings.getInstance().getPreviewUsagesSplitterProportion());
      splitter.setFirstComponent(pane);
      myUsagePreviewPanel = new UsagePreviewPanel(myProject, new UsageViewPresentation());
      myUsagePreviewPanel.setBorder(IdeBorderFactory.createBorder(SideBorder.LEFT));

      Disposer.register(this, myUsagePreviewPanel);
      splitter.setSecondComponent(myUsagePreviewPanel);
      add(splitter, BorderLayout.CENTER);
    }
    else {
      pane.setBorder(IdeBorderFactory.createBorder(SideBorder.LEFT));
      add(pane, BorderLayout.CENTER);
    }

    add(createToolbar().getComponent(), BorderLayout.WEST);

    myTree.getParent().setBackground(UIUtil.getTreeBackground());

    revalidate();
  }
private void layoutPanel()