title: When will bindElement call the real service?
body: <p>Main.view.xml: </p>
  
  <pre><code>&lt;ObjectHeader
      id="objectHeader"
      title="{name}"
      intro="{id}"&gt;
      &lt;headerContainer&gt;
          &lt;IconTabBar
              id="tabBar"
              items="{
                  path: 'assigned',
                  parameters: {expand: 'b, c'} 
              }"
              select="onTabBarSelect"&gt;
          &lt;/IconTabBar&gt;       
      &lt;/headerContainer&gt;
  &lt;/ObjectHeader&gt;
  </code></pre>
  
  <p>Main.controller.js</p>
  
  <pre><code>onMasterSelectionChange : function (sPath) {
      var oSource = oEvent.getParameter("listItem") || oEvent.getSource(),
      // sPath = "/ASet('d')"
      sPath = oSource.getBindingContext().getPath(),
      oObjectHeader = this.byId("objectHeader");
  
      oObjectHeader.bindElement(sPath);
      this._oModel.attachEventOnce("requestCompleted", function(oEvent) {
          var oTabBar =  this.byId("TabBar");
          oFirstListItem = oTabBar.getItems()[0],
          sObjectId = oFirstListItem.getBindingContext().getProperty("id"),
          sDPath = "/DSet('" + sObjectId + "')";
  
          this._getControls(sDPath);
      }, this);
  }
  </code></pre>
  
  <p>I found a strange behavior: when I change the master list selection, sometimes Network will show a "/ASet/assigned" call, but sometimes there will be no call, which cause <code>requestCompleted</code> not fired.</p>
  
  <p>According to: <a href="https://stackoverflow.com/questions/44074712/sapui5-bindelement-doesnt-work-the-second-time">SAPUI5 - bindElement doesn&#39;t work the second time</a>,</p>
  
  <blockquote>
    <p>If you call bindElement with the same path twice, the second time won't actually trigger a new call to get new data, since the path didn't change.</p>
  </blockquote>
  
  <p>But I am sure it is different path. Is there any way that can trigger this call?</p>
  
  <hr>
  
  <p>BTW</p>
  
  <pre><code>oObjectHeader.bindElement({
      path : sPath,
      events: {
          change : function (oData, test) {
          },
          dataRequested : function (oData) {
          },
          dataReceived: function (oData) {
          }
      }
  });
  </code></pre>
  
  <p><code>change</code> can be fired every time I click master list, but <code>dataRequested</code> and <code>dataReceived</code> is never called.</p>