Currently, the TMXL buildables menu can be pulled up from pretty much anywhere ingame except for farm buildings purchased from Robin. It works inside the greenhouse, farmcave and farmhouse, outdoors, and inside NPC houses. If it's not a huge deal to implement, I'd love to see the menu available from farm buildings and be able to place buildables inside sheds/barns/etc. I get no errors when trying to pull up the menu inside a farm building, pressing the hotkey just doesn't do anything.