function topbar_DoFSCommand(command, args) {
  if (command=="change_stage") {
    top.frame_4.document.bottombar.SetVariable("leftArrow_state", "false");
    top.frame_4.document.bottombar.SetVariable("rightArrow_state", "false");
    top.frame_4.document.bottombar.SetVariable("finishArrow_state", "false");
    top.frame_4.goto_stage(args);
  }
}