This bug was fixed in the package software-center - 3.1.0

---------------
software-center (3.1.0) natty; urgency=low

  [ Michael Vogt ]
  * softwarecenter/app.py:
    - use "reopen" instead of "open" in the channels-changed
      callback to ensure that the various views get the right
      signal. This partly fixes #507836, the exceptions will
      stil be there, but the UI will fully recover
  * softwarecenter/backend/aptd.py:
    - do not emit "channels-changed" while installing a purchase,
      this emited already by the update()
  * softwarecenter/db/application.py:
    - if appdetails finds its pkgname in the pending transactions
      but does not have a apt pkg object yet, this means it got
      installed from a newly enabled source, return the right state
      in this case
  * softwarecenter/view/appdetailsview_gtk.py:
    - remove explicit "progress.set_fraction()" in configure() because
      its not needed (gtk.ProgressBar will DTRT) and also we may get
      "xapian reopen" signals in the middle of a transaction, in this
      case we don't want to reset the progress.
  * merged lp:~mvo/software-center/zeitgeist-magic-seif that brings
    basic zeitgeist integration. Many thanks to Seif Lotfy for the
    work on this!
  * merged lp:~mmcg069/software-center/usage-bubble, that makes the
    usage counter look so much nicer :)
  * merged lp:~didrocks/software-center/smarter-app-filtering-level,
    many thanks
  * merged lp:~mmcg069/software-center/selectable-AppDescription,
    many thanks
  * softwarecenter/db/update.py:
    - add mimetypes to the xapian database
  * softwarecenter/db/database.py:
    - support mime search via "mime" search prefix, e.g.
      "mime:audio/ogg" or "softwarecenter search:mime:application/x-cue"
  * merged lp:~seif/software-center/zeitgeist-popular-mimetypes and
    lp:~mvo/software-center/zeitgeist-popular-mimetypes-mvo, that
    brings more zeitgeist love from the unstoppable Seif Lotfy
  * merged lp:~mvo/software-center/3.0-history to bring back version
    numbers in the upgrade history

  [ Delan Azabani ]
  * removed "free" from desktop file description as users can buy
    software from the software center (LP: #656800)

  [ Kiwinote ]
  * softwarecenter/view/appdetailsview_gtk.py:
    - don't eat 'o ' character combinations within bullet points (LP: #646822)
      (test case: software-center deja-dup)
    - scale icon down when setting 'where is it' icon from path (LP: #645062)
      (test case: software-center briquolo (once installed))
  * softwarecenter/view/softwarepane.py:
    - don't offer to 'show 9k items' in searches, as we limit searches to 200
      items (LP: #648988)
      (test case: software-center search:library)
  * softwarecenter/db/update.py:
    - never translate X-AppInstall-Package (fixes eg lp: #658326)

  [ Mohamed Amine IL Idrissi ]
  * Screenshots are now stored all in a single software-center
    directory (LP: #648284)
  * Thumbnails and screenshots are now reused (LP: #648279, #648278)

  [ Gary Lasker ]
  * softwarecenter/view/appview.py:
    - fix intermittent crash in _set_cursor (LP: #617004)
 -- Michael Vogt <email address hidden>   Fri, 15 Oct 2010 17:31:30 +0200