Right clicking after placing the building will get rid of the placement overlay. The same applies to the Flatten Tool and road placement, though it does sometimes take a number of right clicks to make it go away for the Flatten Tool and road placement.
I get why it works this way- building shelters, you may want to place 3 or 4- one after the other. This lkets you do that without having to click [B] to open the building menu over and over. But it is a tad annoying with laying down roads and selecting areas to use the Flatten tool on.I end up having to cancel build commands for roads and flattening on a regular basis.
Right click doesn’t help but thanks for the suggestion. Only happens with buildings that have been built. Happened today and I clicked every button but the ratcatcher building overlay remained on the screen until reloading the game.
Edit: I used WIN key to switch between the game and this forum. Ratcatcher building stopped popping up. I have no idea but at least I don’t have to reload.