Kicker (kde 3.5.4) stops reacting for me (with config took from kde 3.5.3, yes, I upgraded) when system is under load (for example when amarok is rebuilding the whole music library and it is huge enough). I realized that if I kill it and start as other user, i.e. root, it reacts normally (maybe a config issue?)
Can't reproduce. My advice is to remove all used applets and readd/testing them one by one, to find out which one may cause the problem.
I mark it as later because I formatted and I cannot reproduce now. (and it is possible that latest kde version fix this issue I don't know..)
Reopening to change resolution
Resolving as WORKSFORME, as was not reproduced in last 2 years.