I upgraded my trading post and while it was in the middle fo upgrading a trader arrived, clicking directly on the building during upgrade woudl jsut show the build interface but i could still open the normal trader screen by clicking the lil popup icon that appears above the building
after the trader left i noticed it still shows the icon above and shows the “trader 1” tab within the interface.
havent tried yet but was going to check if reloading the save would fix it (im assuming it will) also not sure if it woudl of remained after another trader showing up and continued to keep taking up a spot. felt like it was a good time to have a break so just saved and figured id come back later
side note: Im enjoying the game so far, thank you for ur hardwork