weird, annoying problem in Kontact-3.5.10

[Joseph K.]

I don't expect anyone to have experienced this weirdness before, because I don't think I could reproduce it if I tried. On launch, Kontact sometimes goes into a weird 'frozen' state, not displaying the main screen and displaying the hourglass when I move the cursor over the systray icon. During this time it appears to be downloading new mail, because the unreal mail number increases, but I can't interact with it at all. After a minute or two, it unfreezes. On some occasions the freezing has started after program launch when I click on one of the embedded applications. It all started when... one of those freakish events where I clicked on something in Kontact while it was still starting up, and it made it very upset. It's never been the same.

Anyway, whilst it would be great to fully understand the problem, I'm more interested in fixing it, "nuking the site from orbit" if necessary. I think I have already tried remerging Kontact, but I will try again, and remerging KMail, etc. Can someone please tell me where it might store temporary files that I can delete, and configuration files to backup and then delete? I'll use the output of "equery f <ebuild>" to guide me, but any other explicit suggestions would be appreciated. I'd really like to fix this bug, if possible, by reverting to a clean slate, as it's quite important to me that Kontact functions normally. Thanks, cheers.