I'm receiving several reports by Ubuntu
and Debian users having their desktops crashed as soon as they click the NoScript icon. Yes, your whole session gone, back to your logon page in one move!
Actually this may be triggered by different actions, not necessarily with NoScript installed, or reportedly just by having a long/complex enough interaction with Firefox.
It turns out to be a bug in the xorg-server package, which Ubuntu's maintainers deemed not worth to get fixed before releasing Lucid Lynx.
My understanding is that a fix will be included in next automatic update, but in the meanwhile you can apply the available patch from Bryce Harrington's PPA by issuing the following commands in a terminal:
I was sure I had this crash reported by Debian users as well, but when some of them commented here that they couldn't reproduce it, I double checked and could find Lucid Lynx reporters only. Better so.