How to add another release version to launchpad bug

[Colin Law]

I am having trouble working out how to achieve something in Launchpad.
Bug #824099 is set as Won't Fix for unity (Ubuntu) on Oneiric and
Precise.  However for Quantal I believe that a fix may be possible
using llvmpipe now that unity-2d has gone.  To this end I want add a
new row in the Affects column for unity (Ubuntu) Precise.  I can't
work out how to do that, I have tried clicking on Also Affects Project
but can't seem to do it there.  Does anyone know how to do it?

Colin

[1] https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/824099