Yesterday I cloned the 1.x branch and played a little bit with the layout module and I got to a strange situation.
I added an HTML Element in the layout and placed following html in this element (as html)
<script type="syntaxhighlighter">// <![CDATA[
When I tried to save I got this js - error:
Uncaught SyntaxError: Unexpected token ILLEGAL
Does Layouts not support script at the moment?