title: Update Explorer configuration without restarting it
body: <p>I am wondering is there a way to refresh the HKLM registry key HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer - without restarting the shell.</p>
  
  <p>I would like to be able to do this without restarting explorer. Is there any known way to do that ? </p>
  
  <p>So far, I found only this thing:</p>
  
  <pre><code>RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters ,1 ,True
  </code></pre>
  
  <p>which doesn't work for my case.</p>
  
  <p>It looks insane to me that MS made Explorer so it can't re-read its configuration while running) but you never know.</p>
  
  <p><strong>EDIT:</strong>
  What I try to do is to disable/enable notification area (tray) without restarting.
  The registry key is</p>
  
  <p>Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\</p>
  
  <p>Variable: NoTrayItemsDisplay</p>
  
  <p>Value: 1/0</p>
  
  <p><strong>EDIT 2</strong>
  This is the source code that supposed to work, but on Vista it doesn't, not for notification area, not for my testing dummy which was MyMusic in startMenu (variable NoStartMenuMyMusic)</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;windows.h&gt;
  
  int _tmain(int argc, _TCHAR* argv[])
  {
     DWORD dwRetVal;
  
    int  lResult = SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, (WPARAM)0,
                        (LPARAM)"Policy",
                        SMTO_ABORTIFHUNG, 5000, &amp;dwRetVal);
  
     printf("lResult  = %ld\n", lResult);
     printf("dwRetVal = %ld\n", dwRetVal);
  
     return 0;
  }
  </code></pre>
  
  <p>I tried all sane wparam and lparam values without success. I took the code from <a href="http://www.ureader.com/msg/14841591.aspx" rel="nofollow noreferrer">here</a>
  and dude claims it works...</p>
  
  <p><a href="http://www.eggheadcafe.com/software/aspnet/31604553/getting-explorer-to-rerea.aspx" rel="nofollow noreferrer">This article</a>, however, claims that code doesn't work.</p>
  
  <p>Whats even more ridiculous is that <a href="http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/refrgp.mspx?mfr=true" rel="nofollow noreferrer">gpupdate</a> is suposed to do the job.</p>
  
  <p>Thx.</p>