docs: function (event) {
                  var domEvent = /** @type aria.DomEvent */
                  new ariaDomEvent(event);
  
                  // Retrieve the dom target
                  var target = /** @type HTMLElement */
                  domEvent.target;
  
                  // Close first popup on the stack that can be closed
                  for (var i = this.openedPopups.length - 1; i >= 0; i--) {
                      var popup = /** @type aria.popups.Popup */
                      this.openedPopups[i];
                      if (!utilsDom.isAncestor(target, popup.getDomElement())) {
  
                          if (ariaCoreBrowser.isFirefox) {
                              // There's a strange bug in FF when wheelmouse'ing quickly raises an event which target is HTML instead of the popup
                              if (utilsDom.isAncestor(this._document.elementFromPoint(domEvent.clientX, domEvent.clientY), popup.getDomElement()))
                                  continue;
                          }
  
                          var closed = popup.closeOnMouseScroll(domEvent);
                          if (closed) {
                              break;
                          }
  
                      }
                  }
                  domEvent.$dispose();
              }