docs: function (event) {
                  var domEvent = new ariaDomEvent(event);
                  var target = domEvent.target;
                  var self = this;
                  var popup = this.findParentPopup(target, function (popup) {
                      var navigation;
                      navigation = self._viewportNavigationInterceptor.getNavigationInformation(target);
                      if (navigation == null) {
                          navigation = popup.getNavigationInformation(target);
                      }
  
                      var eventObject = {
                          name: "beforePreventingFocus",
                          event: domEvent,
                          modalPopup: popup,
                          cancel: false,
                          navigation: navigation
                      };
                      self.$raiseEvent(eventObject);
                      if (!eventObject.cancel) {
                          var direction;
                          if (navigation != null) {
                              direction = navigation.direction;
                          }
                          if (direction == null) {
                              direction = 'forward';
                          }
  
                          var reverse = !!(direction === 'backward');
                          ariaTemplatesNavigationManager.focusFirst(popup.domElement, reverse);
                          return popup;
                      }
                      // if the focus is allowed, don't return any popup to bring to the front
                  });
                  if (popup) {
                      this.bringToFront(popup);
                  }
                  domEvent.$dispose();
              }