Two mysterious columns when adding dicts to a CouchGrid

In CouchGrid init, there is an if-clause that's obviously wrong. But when I fixed it, one test fails: test_headings_no_stored_records

It seems to me that when the DictionaryGrid constructor is properly constructed, if you add a dict to the CouchGrid, then its model gets two empty columns between the dicts you provide and the resulting dict from desktopcouch.

Something is definitely wrong here. Is there any reason why the dicts passed to the CouchGrid constructor should not be used to initialize DictionaryGrid?