I'm not sure at all, honestly. I'm trying to figure it out, but I suspect it's an issue with the order in which windows are initialized when starting Unity.
I've got no fix in mind yet, but if I figure one out, you will be the first to know.
Question: Well, that's all well and good - but how do I get rid of that empty window now?
Okay, I've got a solution for you. It's a bit archaic, but I consider myself a pretty archaic guy so it's all OK.
- In the now-empty window, click the little dropdown in the top-right, and select "Add Tab" and add a tab of your choosing (I like to choose Scene).
- Close the window.
- Click on an object in your Hierarchy or Project view, so that the Inspector displays its details.
- You should now be able to open Tidy Tile-Mapper happily.
- If not, click on something else in the Hierarchy or Project view.
- Go to 4.
I'm not sure.
But it does!