setLineClass() fails in 2.22 for {opaque: 0.25;}

[kenwebb]

CodeMirror version: 2.22
Browser: Firefox 10.0.2 and Google Chrome 17.0.963.56
OS: Linux Ubunto 10.10

I have reproduced the issue by cloning a CodeMirror demo. Please compare the following 2 pages:
http://www.primordion.com/Xholon/webEdition/test/testsetLineClass.html
http://www.primordion.com/Xholon/webEdition/test/testsetLineClass222.html

The first URL uses CodeMirror 2.2, and the second uses CodeMirror 2.22 .
My intention is to de-emphasize the first and last lines of the editor text. This works with the first URL and fails with the second.

The original page where the issue occured is:
http://www.primordion.com/Xholon/wb/openwb.php?q=vecsca&t=physics