[ESS] Previous/Next error in ESS tracebug

[Sebastien Vauban]

Hello,

I'm trying to use the debugging features of tracebug, but have problems
understanding how to use 'em all; in particular, I already have troubles
using next/previous error.

As you can see on http://screencast.com/t/VKapcfM8S7m, the only answer
I get (be it in the source buffer or in the iESS buffer) is:

- Before first reference, or
- Beyond last reference

What am I missing?

Best regards,
  Seb

-- 
Sebastien Vauban