const onLeftOrRightInMenu = (comp: AlloyComponent, se: SimulatedEvent<SugarEvent>) => {
    // The originating dropdown is stored on the sandbox itself.
    const dropdown: AlloyComponent = Representing.getValue(comp);

    // Focus the dropdown. Current workaround required to make flow recognise the current focus
    Focusing.focus(dropdown);
    AlloyTriggers.emitWith(dropdown, 'keydown', {
      raw: se.event().raw()
    });

    // Close the dropdown
    AlloyDropdown.close(dropdown);

    return Option.some(true);
  };

export const renderPanelButton = (spec: SwatchPanelButtonFoo, sharedBackstage: UiFactoryBackstageShared): SketchSpec => {
  return AlloyDropdown.sketch({
    dom: spec.dom,
    components: spec.components,

    toggleClass: 'mce-active',

    dropdownBehaviours: Behaviour.derive([
      Unselecting.config({}),
      Tabstopping.config({})
    ]),
    // getHotspot: spec.getHotspot,
    layouts: spec.layouts,
    sandboxClasses: ['tox-dialog__popups'],

    lazySink: sharedBackstage.getSink,
    fetch: (comp) => {
      return Future.nu((callback) => {
        return spec.fetch(callback);
      }).map((items) => {
        return Option.from(createTieredDataFrom(
          Merger.deepMerge(
            createPartialChoiceMenu(
              Id.generate('menu-value'),
              items,
              (value) => {
                spec.onItemAction(comp, value);
              },
              spec.columns,
              spec.presets,
              ItemResponse.CLOSE_ON_EXECUTE,
              // No colour is ever selected on opening
              () => false,
              sharedBackstage.providers
            ),
            {
              movement: deriveMenuMovement(spec.columns, spec.presets)
            }
          )
        ));
      });
    },

    parts: {
      menu: MenuParts.part(false, 1, spec.presets)
    }
  });
};

 se.event().newFocus().bind((nu) => comp.getSystem().getByDom(nu).toOption()).each((nu) => {
   if (Dropdown.isOpen(prev)) {
     Dropdown.expand(nu);
     Dropdown.close(prev);
   }
 });

const renderCommonDropdown = <T>(spec: CommonDropdownSpec<T>, prefix: string, sharedBackstage: UiFactoryBackstageShared): SketchSpec => {
  const editorOffCell = Cell(Fun.noop);
  const optMemDisplayText = spec.text.map((text) => Memento.record(renderLabel(text, prefix, sharedBackstage.providers)));
  const optMemDisplayIcon = spec.icon.map((iconName) => Memento.record(renderReplacableIconFromPack(iconName, sharedBackstage.providers.icons)));

  /*
   * The desired behaviour here is:
   *
   *   when left or right is pressed, and it isn't associated with expanding or
   *   collapsing a submenu, then it should navigate to the next menu item, and
   *   expand it (without highlighting any items in the expanded menu).
   *   It also needs to close the previous menu
   */
  const onLeftOrRightInMenu = (comp: AlloyComponent, se: SimulatedEvent<SugarEvent>) => {
    // The originating dropdown is stored on the sandbox itself.
    const dropdown: AlloyComponent = Representing.getValue(comp);

    // Focus the dropdown. Current workaround required to make flow recognise the current focus
    Focusing.focus(dropdown);
    AlloyTriggers.emitWith(dropdown, 'keydown', {
      raw: se.event().raw()
    });

    // Close the dropdown
    AlloyDropdown.close(dropdown);

    return Option.some(true);
  };

  const role = spec.role.fold(() => ({ }), (role) => ({ role }));

  const tooltipAttributes = spec.tooltip.fold(
    () => ({}),
    (tooltip) => {
      const translatedTooltip = sharedBackstage.providers.translate(tooltip);
      return {
        'title': translatedTooltip, // TODO: tooltips AP-213
        'aria-label': translatedTooltip
      };
    }
  );

  const memDropdown = Memento.record(
    AlloyDropdown.sketch({
      ...role,
      dom: {
        tag: 'button',
        classes: [ prefix, `${prefix}--select` ].concat(Arr.map(spec.classes, (c) => `${prefix}--${c}`)),
        attributes: {
          ...tooltipAttributes
        }
      },
      components: componentRenderPipeline([
        optMemDisplayIcon.map((mem) => mem.asSpec()),
        optMemDisplayText.map((mem) => mem.asSpec()),
        Option.some({
          dom: {
            tag: 'div',
            classes: [ `${prefix}__select-chevron` ],
            innerHtml: Icons.get('chevron-down', sharedBackstage.providers.icons)
          }
        })
      ]),
      matchWidth: true,
      useMinWidth: true,

      // TODO: Not quite working. Can still get the button focused.
      dropdownBehaviours: Behaviour.derive([
        ...spec.dropdownBehaviours,
        DisablingConfigs.button(spec.disabled),
        Unselecting.config({ }),
        Replacing.config({ }),
        AddEventsBehaviour.config('dropdown-events', [
          onControlAttached(spec, editorOffCell),
          onControlDetached(spec, editorOffCell)
        ]),
        AddEventsBehaviour.config('menubutton-update-display-text', [
          AlloyEvents.run<UpdateMenuTextEvent>(updateMenuText, (comp, se) => {
            optMemDisplayText.bind((mem) => mem.getOpt(comp)).each((displayText) => {
              Replacing.set(displayText, [ GuiFactory.text(sharedBackstage.providers.translate(se.event().text())) ] );
            });
          }),
          AlloyEvents.run<UpdateMenuIconEvent>(updateMenuIcon, (comp, se) => {
            optMemDisplayIcon.bind((mem) => mem.getOpt(comp)).each((displayIcon) => {
              Replacing.set(displayIcon, [ renderReplacableIconFromPack(se.event().icon(), sharedBackstage.providers.icons) ] );
            });
          })
        ])
      ]),
      eventOrder: Merger.deepMerge(toolbarButtonEventOrder, {
        mousedown: [ 'focusing', 'alloy.base.behaviour', 'item-type-events', 'normal-dropdown-events' ]
      }),

      sandboxBehaviours: Behaviour.derive([
        Keying.config({
          mode: 'special',
          onLeft: onLeftOrRightInMenu,
          onRight: onLeftOrRightInMenu
        })
      ]),
//.........这里部分代码省略.........