colorhug-client doesn't work after the first install as the gsettings schema database doesn't get updated (so the config options are missing). It only starts to work after you've installed another package that actually triggers the schemas update. The fix is easy just inherit gnome2 eclass, or if you don't want to pull all that in inherit gnome2-utils and call gnome2_schemas_update() from pkg_postinst() and pkg_postrm() Also: Shouldn't colorhug-client have a RDEPEND on argyllcms?
Thanks for the pointer, I'll go work on the ebuild to fix this. And no, the RDEPEND isn't necessary, colorhug-client does work on its own without argyllcms, although it is nice to have it to actually integrate things :)
Now fixed and checked in, thanks for pointing this out.