Button "Anwendungsmenü öffnen" entfernen

// Source file https://www.camp-firefox.de/forum/thema/135594/?postID=1213396#post1213396

(function() {
  if (location.href !== 'chrome://browser/content/browser.xhtml') return;  
  let menuButton = document.getElementById('PanelUI-menu-button');
  if (!CustomizableUI.getPlacementOfWidget('ucjs_PanelUI-button')) { 
    try {
      CustomizableUI.createWidget({
        id: 'ucjs_PanelUI-button',
        type: 'custom',
        defaultArea: CustomizableUI.AREA_NAVBAR,
        onBuild: function(aDocument) {
          let toolbaritem = aDocument.createElementNS('http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul', 'toolbaritem');
          toolbaritem.id = 'ucjs_PanelUI-button';         
          return toolbaritem;            
        }
      });
      if (!CustomizableUI.getPlacementOfWidget('ucjs_PanelUI-button')) {     
        menuButton.style.display = 'none';
        return; 
      };        
    } catch(e) {        
      menuButton.style.display = 'none';
      return;      
    };    
  };
  
  setTimeout(function() { 
   document.getElementById('ucjs_PanelUI-button').appendChild(menuButton);       
   menuButton.setAttribute('consumeanchor', 'ucjs_PanelUI-button');     
  }, 0);
}());