title: CFileDialog - Selected filter and "Hint" showing all files
body: <p>I have CFileDialog and set filter for it (Text files *.txt).<br> When it opens, I see only TXT files, thats right. But! when I'm typing text into filename, the hint (under filename field) is showing all files (files with any extension).<br><br>
  Can be this behavior changed by some flag? I want force hint to show only TXT files.</p>
  
  <pre><code>...
  CFileDialog f(TRUE,NULL,NULL,OFN_HIDEREADONLY|OFN_NOCHANGEDIR,_T("Text files (*.txt)|*.txt|All files (*.*)|*.*||"));
  if( f.DoModal() != IDOK ) return;
  ...
  </code></pre>