Iceweasel on exiting leaves a process behind that consumes 100% CPU power on one core which can only be terminated by killing the PID.
Kanotix seems to have inherited this from Debian. Unfortunately the fix suggested means removing gtk-qt-engine and loosing the integration for Synaptic and other GTK applications which leaves them looking a bit rough.
Firefox proper had exactly the same issue, but the problem disappeared after removing said package.
For archiving, as Google is trawling the page, and for anybody who followed my recommendation of Kanotix and may experience the same problem.
