code: function disable( group ) {
      widgets.forEach( Widget => {
          const els = _getElements( group, Widget.selector );
          new Collection( els ).disable( Widget );
      } );
  }
docs: Disables  widgets, if they aren't disabled already when the branch was disabled by the controller.
  In most widgets, this function will do nothing because all fieldsets, inputs, textareas and selects will get
  the disabled attribute automatically when the branch element provided as parameter becomes irrelevant.
  
  @param  { Element } group The element inside which all widgets need to be disabled.