title: Best way to hide a window from the Alt-Tab program switcher?
body: <p>I've been a .NET developer for several years now and this is still one of those things I don't know how to do properly. It's easy to hide a window from the taskbar via a property in both Windows Forms and WPF, but as far as I can tell, this doesn't guarantee (or necessarily even affect) it being hidden from the <kbd>Alt</kbd>+<kbd>↹Tab</kbd> dialog. I've seen <em>invisible</em> windows show up in <kbd>Alt</kbd>+<kbd>↹Tab</kbd>, and I'm just wondering what is the best way to guarantee a window will <em>never</em> appear (visible or not) in the <kbd>Alt</kbd>+<kbd>↹Tab</kbd> dialog.</p>
  
  <p><strong>Update:</strong> Please see my posted solution below. I'm not allowed to mark my own answers as the solution, but so far it's the only one that works.</p>
  
  <p><strong>Update 2:</strong> There's now a proper solution by Franci Penov that looks pretty good, but haven't tried it out myself. Involves some Win32, but avoids the lame creation of off-screen windows.</p>