World Editor has stopped saving map on Save As

I've been creating new maps by using Save As on existing maps, starting with vanilla maps. Yesterday, Save As stopped working.

Typically, Save As creates a complete copy of the map and changes most of the file paths in key json files. As of yesterday, all it saves is the main.decals.json file.

My normal steps to save a map:

1. Open the map I want to use as a base (today it's the vanilla template).
2. Hit F11 to open World Editor.
3. Click File > Save As
4. In the file dialog, type a new folder name in the appropriate field. (See screenshot)
5. Click Create Folder. The file paths in the main box disappear as the file dialog enters the new folder.
6. Click Open. ...(Why "Open"? Why not "Save" or "Create"?)

This normally results in a few seconds of CPU activity as the original game folder is copied to the new path under my /levels/ folder, but now the dialog closes instantly, and I just get the above-mentioned decals file.

Did I trigger this somehow? I've done a full cache cleaning, but it's still misbehaving.

 

Do you normally copy folders, then change all the paths in your text editor?

 

In that case, I think I'll take the opportunity to start fresh with something completely blank, maybasic starting point.e smallgrid or the vanilla template. It will be good practice to build data files from a really basic starting point... although maybe I should start using 1.5 materials before the old ones get phased out.

 

Interestingly enough, the first map this failed with was smallgrid.

I'm playing around with a copy/paste of the template map now; very few paths to rename, so it's a good sandbox.