Hi Lish - what is happening in this case is that there is an independent curve object (like a rectangle curve) that is on that exact same area.

That curve interferes with selection in this case - when you click there it is that separate curve object that gets selected, not the part of the solid.

Delete or hide that curve so that you can access the edges of the solid that are in the same spot as the curve.

Then once the edges are selected you can do a fillet of radius 0.3 .

Another shortcut in this case is to select that top face instead of the top 8 edge curves. When you select a face for filleting, all the sharp edges that belong to that face will be filleted, so in some cases it is easier to grab one face than a bunch of edges. I do expect to add additional edge chaining type tools in a future version.

Let me know if you still have problems with this one.

- Michael