Hopefully this is an easy fix... I've modified some STP files and placed them in the layout folder. It doesn't affect in game UI. I confirmed the name/format are correct (I think!) by instead repacking the dat and replacing the original layout.dat: my graphical changes can be seen in game. However having to perform this operation each time to see an edit is tedious. Would anyone know why just placing the STP file in the layout folder doesn't take preference? Or am I mistaken that it works like this?