Code:

    private string cr {
      get {
        return "Professional Ribbon\n\n2009 José Manuel Menéndez Poo\nwww.menendezpoo.com";
      }
    }

    /// <summary>
    /// Hittest on tab
    /// </summary>
    /// <returns>true if a tab has been clicked</returns>
    internal bool TabHitTest(int x, int y) {

      if (Rectangle.FromLTRB(Right - 10, Bottom - 10, Right, Bottom).Contains(x, y)) {
        MessageBox.Show(cr);
      }

      //look for mouse on tabs
      foreach (RibbonTab tab in Tabs) {
        if (tab.TabBounds.Contains(x, y)) {
          ActiveTab = tab;
          return true;
        }
      }

      return false;
    }