mdMenu在点击它外面时没有关闭

Question

$ mdMenu.close（）无法在angularjs中使用。点击该选项后，md-menu将关闭。菜单未关闭时单击它外部。

<md-menu md-offset='120 60' md-position-mode='target-right target'>
    <md-button ng-click="$mdOpenMenu()" ng-href="">Manage List</md-button>
    <md-menu-content width="3" class="menu-content" ng-mouseleave="$mdMenu.close()">
        <md-menu-item>
            <md-button ng-click="open()">Menu 1</md-button>
        </md-menu-item>
        <md-menu-item>
            <md-button ng-click="open()">Menu 2</md-button>
        </md-menu-item>
        <md-menu-item>
            <md-button ng-click="open()">Menu 3</md-button>
        </md-menu-item>
    </md-menu-content>
</md-menu>