[ESS] ?while hangs emacs

[regcl]

I use ESS what seems like 24/7. It is truly great stuff & this is just
a nit, but... in an R session running in emacs under ess like this ...

*R*            Bot L5288  (iESS [R]: run VHl ElDoc)

... when I type ...

?while

... it hangs emacs. 

I'm using ...

GNU Emacs 24.3.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.18.9) of 2013-05-25 on <redacted>
ess-version : 12.09 [rev. 5167 (2012-09-24)]

... both installed from source.

BTW, also hangs for

?if

Is this a known issue?

Might it be fixed in 13.05?

Best,
regcl