title: Tips on troubleshooting an EStackoverflow exception in the Delphi IDE
body: <p>I'm running Delphi 2009. When I try to view a form in the form editor I keep getting a stack overflow. So I did what anyone else would do. I used Delphi to debug itself or rather another instance of the IDE.</p>
  
  <p>So I know where the overflow is occuring I just don't know what to do about it. There is a custom component on this form that is intercepting calls to <code>TForm.WindowProc</code> so it can respond to certain winapi messages. The stack overflow is occuring when the component invokes the <em>real</em> <code>WindowProc</code>.</p>
  
  <p>When I break on the exception the call stack is filled with hundreds of calls to:</p>
  
  <pre><code>delphicoreide120.@Comppalmgr@TComponentPalettePageItemDelegate@CheckValid
  </code></pre>
  
  <p>So far I haven't had any luck tracking down the actual message being passed to WindowProc.</p>
  
  <p>Any help would be appreciated.</p>
  
  <p><strong>Update</strong></p>
  
  <p>I've made some progress. Tracked down the message that appears to be setting this off. It's WM_CHILDACTIVATE. When this message gets passed to the form's <code>WindowProc</code> it sets off a series of calls within the IDE that ends with a stack overflow. Now I just need to figure out why.</p>