Reactive columns

I am trying to make the columns reactive, by having a mongo document containing the list of columns to display. but this does not seem to work. I tried using autoruns but it failed, as well.

How can I reactively change the columns?

Reproduce the reported setup with a Mongo document supplying the columns and an autorun, then trace the tabular column configuration and reactive update entry points. Done means the displayed columns update when the document changes; the issue does not name specific files or tests to run.

Written by the indexing model from the issue text.