How to reproduce this bug:
1. Do a search with Synaptic.
2. Do a second search.
3. Click in the search space to select the words of the first search
and modify them.

What's happening?
It's impossible. If started from a terminal, it writes something like:
I think it should be possible to modify the first query, to launch a
third search.
(As in the 0.70~pre1 version, to which I'm going to downgrade.)

Nota Bene:
This bug has already been reported here:
<https://bugs.launchpad.net/ubuntu/+source/synaptic/+bug/688769>