title: NSTextField isn't active on NSPopover attached to NSStatusItem
body: <p>I have a NSStatusItem created like this:</p>
  
  <pre><code>statusItem = [[NSStatusBar systemStatusBar] statusItemWithLength:NSVariableStatusItemLength];
  [statusItem setTitle:@"DS"];
  [statusItem setHighlightMode:YES];
  [statusItem setAction:@selector(StatusClicked:)];
  [statusItem setTarget:self]; 
  </code></pre>
  
  <p>I also have a popover with customview. On the view I have textfield: <a href="http://d.pr/i/CWbr" rel="nofollow">http://d.pr/i/CWbr</a></p>
  
  <p>My popover is shown like this:</p>
  
  <pre><code>- (void)StatusClicked:(id)sender {
      [self.popover showRelativeToRect:[sender bounds] ofView:sender preferredEdge:NSMaxYEdge];
  }
  </code></pre>
  
  <p>From a debuger I learned that <code>sender</code> here is an instance of <code>NSStatusBarButton</code> class.</p>
  
  <p>The problem is that when the popover pops I can't type in textfield, it apears inactive: <a href="http://d.pr/i/q18U" rel="nofollow">http://d.pr/i/q18U</a></p>
  
  <p>The button is working though.</p>
  
  <p>I think that problem is in the view I pass to <code>ofView:</code>. I tried to change it to a control on window like this:</p>
  
  <pre><code> [self.popover showRelativeToRect:[sender bounds] ofView:self.postText preferredEdge:NSMaxYEdge];
  </code></pre>
  
  <p>And textfield became active (<a href="http://d.pr/i/DmTz" rel="nofollow">http://d.pr/i/DmTz</a>) but I have no idea why this helps.</p>
  
  <p>Why does my popover textfield becomes inactive when poped from menu?
  Why button works?
  How can I make textfield active?</p>
  
  <p>P. S.
  My app is <code>Application is agent (UIElement)</code></p>