Collectible Card Game Headquarters

Describe the Bug:
A Plains that has been targeted by Quarum Trench Gnomes's activated ability produces when tapped for mana. fixed

Which card did behave improperly ?
Quarum Trench Gnomes

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
CoRM15 mini3, duel

What exactly should be the correct behavior/interaction ?
A Plains that has been targeted by Quarum Trench Gnomes's activated ability produces when tapped for mana.

Are any other cards possibly affected by this bug ?
-

Actually, basic land and original duals are still hardcoded and I won't touch them before Korath is back, so they can't interact with the Gnomes at all...

Tests in dev.
It works for basic Plains and plains that produce only white mana now, but not for any plain that can produce more than one type of mana like duals or Temple Garden. Those too, when they select to produce white mana they should be affected but not when they select other color.