title: mdDialog show twice in AngularJS md-autocomplete
body: <p>i am using md-autocomplete to show data to user  </p>
  
  <pre><code>  &lt;form name="searchForm" ng-submit="$event.preventDefault()"&gt;
                  &lt;md-autocomplete
                      md-no-cache="true"
                      md-selected-item="ctrl.selectedItem"
                      md-search-text="ctrl.searchText"
                      md-items="item in ctrl.querySearch(ctrl.searchText)"
                      md-item-text="item.display"
                      md-min-length="0"
                      placeholder="enter Name"
                      md-search-text-change="ctrl.searchTextChange(ctrl.searchText)"
                      md-selected-item-change="ctrl.selectedItemChange(item,$event)"
                      &gt;
                      &lt;md-item-template&gt;
                          &lt;span md-highlight-text="ctrl.searchText" md-highlight-flags="^i"&gt;{{item.display}}&lt;/span&gt;
                      &lt;/md-item-template&gt;
  
                      &lt;md-not-found&gt;
                         not found anything!
                      &lt;/md-not-found&gt;
                  &lt;/md-autocomplete&gt;
              &lt;/form&gt;
  </code></pre>
  
  <p>when user click on result,it show on popup using $mdDialog  </p>
  
  <pre><code> function selectedItemChange(item,ev) {
  
      $mdDialog.show({
          locals: { drugData: item },
          controller: DialogController,
          templateUrl: 'DIALOG.TMPL.html',
          parent: angular.element(document.body),
          targetEvent: ev,
          clickOutsideToClose: true,
          fullscreen: false  
      });
      self.selectedItem = '';
  
  }  
  </code></pre>
  
  <p>i use <code>self.selectedItem = '';</code> to clear search text after user click but it cause $mdDialog showed twice and item that passed to dialog is become empty in  second time.how can i prevent dialog show twice?<br>
  is there something like md-selected-item-click?<br>
  i want to show dialog when ever user click on result and it happend only once  </p>