Took me a bit, but here's one way:
1) Log in - at this point everything works fine. Click on the Move Building button and the "Done" button is there.
2) Visit another player - doesn't matter who, and you don't need to do anything, just visit their city
3) Go back to your city
At this point the bug occurs. Click on the Move Building button and the "Done" button is no longer there.
Reloading the game fixes it - until the next time you visit a player.