title: How do I find out who called SendMessage?
body: <p>I'm attempting to debug a problem with my Windows installation. The details don't particularly matter, but I'm looking for the answer to the following question:</p>
  
  <blockquote>
    <p>explorer.exe receives a WM_SETTINGCHANGE message. In WinDbg, I can break at the appropriate WndProc. How do I find out who sent the message? That is: is there any way to trace this back to the process that called <code>SendMessage(HWND_BROADCAST, WM_SETTINGCHANGE, ...)</code>?</p>
  </blockquote>