title: extjs 4 form still has record set after form.reset();
body: <p>I have a grid bound to a form the forms submit action is to update the loaded record if there is one and add a new record if its a blank form.  but if I select a record first and then call</p>
  
  <pre><code>myGrid.getSelectionModel().deselectAll();
  myform.getForm().reset(); 
  </code></pre>
  
  <p>to clear the form so I can add a new record it overwrites the previously selected record with an update.</p>
  
  <pre><code>record = myform.getRecord();
  if(record){
  record.set(values);
  }
  </code></pre>
  
  <p>shouldn't myform.getRecord(); be null after a reset?  how do I clear the record selection?</p>