Still not exactly sure what is going on? Check out those actions being enabled or disabled?
Okay, I can recreate this as well. The enable code seems to falter because hr is a self closing tag.
If I replace <hr/> with <hr></hr> (legal in xhtml) then it all functions just fine.
I tried with other normally self closed tags like <img/> and it functioned just fine.
The problem only seems to happen with hr tags that are single. I wonder if the code is seeing a two character tag starting with h and getting confused with it and headers?
Edit: After more tests it only does not work with hr that is self closed. It works after a self-closed br and even made up self-closed tags like hrr or vhr or h or even hv.
The problem seems to be specific to self-closed hr tags only.
That is very strange!