I'm sure I'll embarrass myself here, but I can't seem to select individual control points on a curve in edit mode. Not by box select, not by circle select, not by clicking on them. In box select mode, for example, Blender draws the affordance for the box, but nothing gets selected.
Select All (A) works. Deselect all (A, A) works. Editing a mesh object works normally. I can delete the curve, make sure nothing is selected, add another, and I get the same problem. I can add a mesh object and edit it normally. The problem only seems to affect curves of all types, and only in this file.
This is on 2.92.0 on Win10. New files and other recent saves are not affected.
Ideas?