I fixed a bug in the spinbuttons and pushed it right away. Each spinbutton has an id, which is essentially just an int. The normal threshold have the values 0... (NUM_YIELDS - 1) The trader export has NUM_YIELDS...(2*NUM_YIELDS - 1) Trader import ended up with NUM_YIELDS +1...(2*NUM_YIELDS) This mean that import food ended up with the same spinbutton as export luxury food. Clearly that is not what we want. I changed the import range to (2*NUM_YIELDS) to (3*NUM_YIELDS - 1) I also updated some comments in CvCity. The code is correct, but the comments had copy paste errors and I don't like comments not matching the code. It can easily lead to confusion and bugs later on.