User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 (.NET CLR 3.5.30729) On the page in the example, look at the left hand side. See the Facebook logo? This logo is a image link inside a P tag, that lies OUTSIDE of the FORM element's closing tag. Firefox is not only rendering it INSIDE the FORM tag, but Firebug HTML view also lists this P tag as inside the FORM tag as well. Reproducible: Always Steps to Reproduce: 1. Go to site 2. look at source code 3. also look at firebug HTML view for page (this shows the P being INSIDE the FORM, when it IS NOT) Actual Results: Renders P tag as if it were inside the FORM tag Expected Results: The P tag to be displayed outside of the FORM, as it is in ALL other browsers

This is a parser issue with the old HTML parser. In particular, this markup: <form> <p> </form> <p>Where should this be?</p> leads to the </form> being ignored because of the "unclosed" <p>. The page has just such markup near the end of the form (seems to have a <p> where it meant to have a </p>). The problem is corrected with the HTML5 parser, so marking dependent on that landing.

Why not dup against bug 22480?

Because I didn't find it. ;)