There was a pesky bug in CAREO for the past couple of months, where a non-themed component with a hyperlink would nuke the theme setting for that session, possibly also improperly rendering whatever page was linked to the hyperlink.
I've finally tracked it down and squashed it (it was low priority, mostly cosmetic), and it seems to work better. Theme setting is now properly stored in (and retrieved from) the session, so hyperlinks should work more reliably (like, for instance, in the WOTabButtonPanel in Metadata view).