I have sIFR3 working nicely, but whenever I open Firebug in FF 3.5, any attempt to inspect the page breaks? sIFR3. The page reverts to it's non-sIFR3 text. Not sure what I'm missing.
Updated*
You'll notice the same behavior on one of the sample sites listed on the sIFR3 wiki: http://www.lightweb.pl/