I was testing my first template and I discovered that I can leave comments with every html tag (I've checked this on low level account, every user can put some strange code like
</div><div style="position: absolute; width: 100%; height: 100%; background: #000; color: #fff;">Buahahaha! I don't like you!</div>)
I don't know if there is either error in the template or in WordPress code. That's my first layout and I may missed something important.