[TYPO3-english] Typo3 strange html "repair"

[Pero Matic]

Hi. I made some changes to one extension which returns piece of html. In 
that piece of html there is also this:

<option value="1" selected="">Something</option>

The problem is that my original $content value prior to return from 
extension class looks like:

<option value="1" selected>Something</option>

I made echo $content; prior to return from class so I know this for sure.

Now, does anybody knows where this ="" (in front of selected) came from ??? 
Thx!