private SolutionBrowserPanel() {
    RootPanel.get().getElement().getStyle().setProperty("position", "relative");
    dragController = new SolutionBrowserDragController(contentTabPanel);
    instance = this;

    ExecuteUrlInNewTabCommand.setupNativeHooks();
    SolutionBrowserPanel.setupNativeHooks(this);

    solutionTree.addTreeListener(treeListener);
    initializeExecutableFileTypes();
    buildUI();
  }