Findbar automatisch leeren

(function() {

  if (!window.gBrowser)
    return;

  async function doFindbar() {
    await gFindBarPromise;

    gFindBar.open = function open() {
      this.findMode = this.FIND_NORMAL;
      this._findFailedString = null;
      this._updateFindUI();
      if (this.hidden) {
        this.removeAttribute("noanim");
        this.hidden = false;
        this._updateStatusUI(Ci.nsITypeAheadFind.FIND_FOUND);
        let event = document.createEvent("Events");
        event.initEvent("findbaropen", true, false);
        this.dispatchEvent(event);
        this.browser.finder.onFindbarOpen();
        return true;
      }
      return false;
    };
  };

  doFindbar();

  gBrowser.tabContainer.addEventListener('TabSelect', function() {
    if (!gFindBarInitialized)
      doFindbar();
  });

})();