... tittle says all.
I am told that this is a bug that happens if you upgrade a building before settler arrives.
I did so.
No i have a butcher building lvl 2, that is idle due to no worker there.
I have a lot of free settlers,
tried logging in and out,
tried getting my free settlers to 0, (building military units) and waiting to go to 1...2....3 again,
but still my building is idle.
I am told i must tear it down.
It is a very disappointing bug,