title: Security Manager vetoes action in Greasemonkey Script!
body: <p>I'm trying to prevent my Greasemonkey script from executing within IFRAMEs. I'm doing so by using <code>if (window.top != window.self) return;</code>. As soon as I insert that line right after the metadata header, the error console throws out a "Security Manager vetoed action" indicating this exact line of code. There's no additional information available.</p>
  
  <p>I'm using Firefox 3.6.10 and the latest Greasemonkey extension. Oh, I'm new to user scripts but even after some time looking for an answer I didn't find anything at all.</p>