I was going to post this in the original thread but since the last answer is from June, I didn’t want to necro that post.
It’s a great mod and, so being, I couldn’t let it with that annoying error… Besides the fact it was disturbing me and probably the Benefactor too so, why not? 
This is same mod as the original(nothing added or removed)
but without the UI Error when closing the craftsman window.
stonehearth_expanded.zip (2.4 MB)
If you already have the mod installed and don’t want to download again, you can edit it by yourself, it’s very simple:
-
Just open it
-
CTRL+F and search for “setFocus” or just “Focus”. You will get a line like radiant.blahblahblah.setFocus = null;
-
Remove this line from existence and save it.