Comment # 14 on bug 1199699 from Yasuhiko Kamata

Sorry for delaying reply.

> But since this happens with some icon themes and not others, maybe the theme itself could be fixed?

Yes, your point is correct.
Some icon images have an incorrect (a little large) size.

You can fix icons with:

cd /opt/kde3/share/icons/slick; for i in *; do if [[ $i =~ ^[0-9]+x[0-9]+$ ]];
then find $i/ -type f | xargs -n 1 -i sh -c "mv {} {}.orig; convert -resize $i
{}.orig {}"; fi; done

After running it, this bug was solved in my environment.
Could you please check in your environment?