/** Initializes and registers the context menu. */
  protected void initContextMenu() {
    MenuManager menuMgr = new MenuManager(contentService.getViewerDescriptor().getPopupMenuId());
    menuMgr.setRemoveAllWhenShown(true);
    menuMgr.addMenuListener(
        new IMenuListener() {

          public void menuAboutToShow(IMenuManager manager) {
            fillContextMenu(manager);
          }
        });
    TreeViewer commonViewer = commonNavigator.getCommonViewer();
    Menu menu = menuMgr.createContextMenu(commonViewer.getTree());

    commonViewer.getTree().setMenu(menu);

    actionService.prepareMenuForPlatformContributions(menuMgr, commonViewer, false);
  }