I have a largish level that I successfully exported to FBX out of WED, then converted to OBJ which I then imported into Blender so I could remove duplicate vertices and do other cleanup, then I exported (again, successfully) from Blender to OBJ, then converted to FBX, and then imported into WED. When the level shows up in WED, it is as a model. Fine, so I select it, and then in its properties I de-select the "concave" check box, and I get the message "Convert mesh to block?" and I hit okay.

...and nothing happens.
The "concave" check box just checks itself again as if I hadn't chosen anything.
And for the record, I tried importing the FBX both with and without de-selecting the "concave" option in the import dialogue, and I get the same result either way.

Is this a bug? Or am I missing something? I want to convert my level, which is currently in model form, back to level "blocks", and I thought 3DGS supported this option.

Thanks in advance...