title: Encountering a FileSystemRights value that isn't defined in enumeration
body: <p>I've written an application that examines all of the file system permissions on a directory.</p>
  
  <p>A directory has a number of access rules (of type <code>FileSystemAccessRule</code>).</p>
  
  <p>Each access rule has a property <code>FileSystemRights</code>, which is a flag enumeration.</p>
  
  <p>When running this, I keep encountering a <code>FileSystemRights</code> value of <code>268435456</code> (which comes to <code>0x10000000</code> in hexadecimal).</p>
  
  <p>This value just doesn't appear in enumeration! It's actually higher than the highest single flag value (<code>Synchronize</code>, having a value of <code>0x100000</code>).</p>
  
  <p>Does anyone know what this is?</p>