title: PngImageList: why Items.Count incorrent?
body: <p>If I lock <code>TPngImageList</code> (Delphi7 version) using</p>
  
  <pre><code>  L.BeginUpdate;
  
    L.PngImages.Add.PngImage.LoadFromFile(s1); 
    N1:= L.Count;
  
    L.PngImages.Add.PngImage.LoadFromFile(s2); 
    N2:= L.Count;
  
    L.EndUpdate;
  </code></pre>
  
  <p>then, seems, I get wrong N1 / N2, because <code>Count</code> is incorrent during <code>Begin/EndUpdate</code>. How to read count of icons then?</p>