history completion oddity

[Peter Stephenson <pws@cambridgesiliconradio.com>]

I expect Sven will tell me this is the way it should work (or has to work),
but it's worth a try...

history completion (ESC-/) on
  % echo ${PWD
does nothing.  On
  % echo ${PWD/
it gives me what I expect (don't ask):
  % echo ${PWD/bc01/bc01/test}/$f

I would guess that something visceral is grabbing potential parameter
completions before the history code can do anything --- given the second
result, the list of history words is OK, and also, more subtly, it's not
falling over on the incompletely parsed parameter.  I didn't get very far
looking at the trace output, a large chunk of which (in my case) seems to
be testing for colouring strings.

-- 
Peter Stephenson <pws@cambridgesiliconradio.com>
Cambridge Silicon Radio, Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070