Card Errata talk:Ancient City - Rainbow Ruins

argh! Please, tell me how come that the crystal beast cards in s/t zone are not treated as "under my control". As I know, the player that activates a continuos spell is treated as the CONTROLLER of that spell card. Ergo, if I have Crystal beast continous spells in my s/t, it means that I could use tham as tributes for Rainbow dragon, or the effect 3+ of this field card.