fluxbox-1.3.3 has a bug with timers that causes it to become unusable with 100% CPU hang. This bug can be triggered in various ways. upstream is working on a solution, first patch available in this bug report: http://sourceforge.net/tracker/?func=detail&aid=3600143&group_id=35398&atid=413960
1.3.5 is in the tree: "A nasty, little bug went undiscovered into 1.3.3 and prevented the logic commands from working. So, if you happen to use any of the logic commands like 'if', 'and' or .. well .. 'or' in your keys-file: This is the release that fixes that for you. Nothing else was added or fixed." Please test!
Also: Critical Bugfixes in 1.3.4: All timer based problems are fixed now
Yes, it was fixed upstream. The fix works fine for me. But I still can't upgrade due to a segfault issue http://sourceforge.net/p/fluxbox/bugs/1077/ but it only happens in very specific configs (which is attached in the bug report) and apparently no one except me was able to reproduce the issue yet (you're invited to try yourself). And upstream can't fix this one as they're not able to reproduce. Anyway, that'd be a different bug report then.
fluxbox-1.3.3 was removed