Construct/Demolish tabs disappear?

[Galdat]

I have a bug submission into Playmesh, but it hasn't had a response yet. I thought i would try my luck here. I have been demolishing buildings in a city to bring it to the point where it just produces guardians. It at one point produced scholars. For some reason half way through down-sizing, the construct/destruct tab buttons have disappeared. Is this normal? If so, why? And for what it is worth, i reinstalled the game and it didn't change anything.