To remedy just go to the raid section and click on the hide bar option...
I got the error too.
Hm, hide mana bar or? Already hidden. Strange. I'll rollback previous version I think.
Edit: Went back 1 version and bars where gone.
Ok I never said mana bar....I said go to the "RAID" section and hide bar or frame, you will see what i mean.
And yes reverting to previous version fix this too.