Citation problems

I am not sure if this is a reftex (reftex-version says 4.26) or an 
auctex problem. My first guess was reftex, but since the problem has 
appeared rather recently and I have updated auctex but not reftex I am 
not sure.

Anyway, if I press C-c [ in the small document below and choose a 
rerefence in references.bib, it inserts something like 
\cite[]{Murota:2000}, i.e. there is an extra pair of brackets that I do 
not want.

Anyone got a clue what is happening here? Who is at fault, me, auctex, 
or reftex?

Regards,
	Erik

\documentclass[a4paper]{article}
\bibliographystyle{plain}

\begin{document}
In \cite[]{Murota:2000}.
\bibliography{references}
\end{document}



Emacs  : GNU Emacs 21.3.50.1 (sparc-sun-solaris2.9, X toolkit, Xaw3d 
scroll bars)
  of 2005-02-08 on alfa.isy.liu.se
Package: AUCTeX CVS-5.482 (2005-02-01)

current state:
==============
(setq
  window-system 'x
  LaTeX-version "2e"
  TeX-style-path '("style/" "auto/" "/home/fs/frisk/Emacs/mystylesauctex/"
		  "/home/fs/frisk/Emacs/auctex/style/"
		  "/home/fs/frisk/Emacs/auctex/auto/")
  TeX-auto-save t
  TeX-parse-self t
  TeX-master t
  )

-- 
---------------------------------------------------------------------
Erik Frisk                            email:         [email protected]
Dept. of Electrical Engineering         tel:            +46 13 285714
Linköping University                    fax:            +46 13 282035
S-581 83 Linköping
SWEDEN                               http://www.fs.isy.liu.se/~frisk/
---------------------------------------------------------------------