title: How to show a title of document window without icon?
body: <p>Now I drag a file to the app icon in the dock, this app is based on document . I found that no little image on the left of window title after the app is run and the mainwindow is open . but when I drag a file to the dock icon before the app run and use this method to run the app , a little image on the left of window title to show the file ,just like the xcode etc.
  Now I want to show the little image both way or not to show the little image both way , How to do ? I think that it maybe the window property based on document , but I don't know how to fix it ? Thanks!<a href="http:///Users/jinxin/Desktop/Mydocument.png" rel="nofollow noreferrer">alt text http:///Users/jinxin/Desktop/Mydocument.png</a></p>
  
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  <p>I used the <code>[mainWindow setTitle:tmp];</code>, but icon still appear. when I used <code>setTitleWithRepresentedFilename:</code> I found that both icon and window title name both are modify, in the document class I overload the <code>-(void)displayName;</code> so I want to the window title is fixed anytime.</p>