Describe the Bug:If you have black mana available then you can't use blue mana to start Oona's ability (when you click on Oona it asks for black mana and if you click cancel you don't get an option to use blue, it just cancels it).
Which card did behave improperly ?Oona, Queen of the Fae Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)PtoM
What exactly should be the correct behavior/interaction ?You should be able to use either blue or black mana to start the ability regardless of whether you have black available.
Are any other cards possibly affected by this bug ?Possibly other cards that use the split mana, but I haven't found any.