[1.21p] Roadbuilding + "MTH offering to buy IP" decision can make IP go negative

[Magirot]

Going to other menus causes the decision to refresh, but roadbuilding is different since you can keep the decision dialog open while building roads.

If you use IP on roads and then click yes to the offer, your IP can go negative. So the values probably have to be rechecked after player makes the decision.

Edit: Another case where this can happen is if you set the zone to another SHQ - the "Change Zone SHQ" dialog doesn't cause the decision dialog to close or refresh.

[Vic]

Making a note to look at this next time I touch on the UI. Well spotted.