title: Close all open dialogs
body: <p>If I open two dialogs</p>
  
  <pre class="lang-js prettyprint-override"><code>dialogBusy = new sap.m.BusyDialog();
  dialogBusy.setShowCancelButton(true);
  dialogBusy.setTitle("1");
  dialogBusy.open();
  
  dialogBusy = new sap.m.BusyDialog();
  dialogBusy.setShowCancelButton(true);
  dialogBusy.setTitle("2");
  dialogBusy.open();          
  dialogBusy.close();         
  //dialogBusy.close();
  </code></pre>
  
  <p>When I call close function, I close only the 2nd dialog (correct).
  How can I close all dialogs?</p>