[AUCTeX] reftex completing bibtex keys

[Tyler Smith]

Hi,

In the Reftex manual, section 4.1 Creating Citations, it says:

  In order to create a citation, press `C-c [' ...
  When entering the regular expression, you can complete on known
  citation keys.

When I am running Auctex with Reftex running, pressing C-c [ brings
up the citation style buffer, followed by the Regexp prompt. I can enter
search terms and get the expected list of refences from my .bib file.

However, I can't get any sort of completion. Pressing tab produces the
message [No match], regardless of whether I started entering a key or
not. Should I be able to get tab-completion of bibtex keys? If so, how
do I set it up?

Thanks,

Tyler

Reftex 4.31
Auctex 11.86
Emacs 24.0.94.1