[OS X TeX] BibDesk columns have disappeared

[Theo Moore]

Today, I opened BibDesk, and I discovered that, for some reason,
BibDesk does not display any of my columns! For example, I can add a
new entry, but the area where the entries usually show up is entirely
blank. See the image here:
http://tinypic.com/r/1440m7n/7

I tried looking under View--> Columns, and all the columns I expect
are checked (e.g. Author, title, etc.). I also tried Autosize all
columns.

This seems really stupid, but I can't figure out what happened.
Nothing was changed as far as options from the last time I accessed
BibDesk.