protected BorderLayoutPanel fillMainPanel(BorderLayoutPanel mainPanel, Tree tree) {
    JComponent toolbar = createToolbar(mainPanel, tree);
    tree.setBackground(UIUtil.getToolTipBackground());
    toolbar.setBackground(UIUtil.getToolTipActionBackground());
    new WindowMoveListener(mainPanel).installTo(toolbar);
    return mainPanel.addToCenter(ScrollPaneFactory.createScrollPane(tree, true)).addToBottom(toolbar);
  }
protected BorderLayoutPanel fillMainPanel(BorderLayoutPanel mainPanel, Tree tree)