[GTK3] Scrolling list view with the keyboard doesn't work

In Bug #524567, The scrolling is rather slow. There's a lot of flashing of "More Info" and "Install" buttons, visually trailing behind the highlighting of the selected item.

This bug is caused by the fact that we have a treeview (which implements its own scrollable interface) parented by a vbox itself parented by a viewport. This combination seems to break the treeview keyboard scrolling.

This widget arrangement was introduced to allow the appcount to be displayed at the bottom of the listview.

This is a tricky bug to fix as it stands. My proposal is to move the appcount into the header widget (the widget with the sort mode combobox) beneath the categorisation label. This way we can simplify the widget arrangement, in turn fixing this bug.

Moreover, while the appcount is probably not of huge interest to users, I believe the appcount in the header, where it is always visible makes more sense than hiding it at the bottom of a (potentially long) list.

I have linked a branch which demonstrates the proposal.

Nice suggestion, but I think the number of items probably isn't nearly important enough to be shown that prominently.

Could the problem be fixed instead by making the heading and menu at the top, and the count at the bottom, scroll together with the list? I.e. they act as an unselectable first item for the list. That's what I'd half-imagined originally, though I see that I never made it explicit in a sketch. Would that avoid the need for the vbox?

If not, I think the next best solution is to drop the count altogether until the treeview breakage is fixed.

I can't come up with a simple fix for this issue, unless anyone else knows a nice way to solve this, i think we will have to go with mpt's plan C and drop the app count altogether for the time being. :(

See linked branch for the change.

This bug was fixed in the package software-center - 4.1.22

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software-center (4.1.22) oneiric; urgency=low

  [ Gary Lasker ]
  * data/ubuntu-software-center.desktop.in,
    debian/rules,
    setup.py,
    software-center,
    software-center-gtk2,
    softwarecenter/toolkit.py:
    - launch the new UI using 'software-center', add script
      to launch the old version if feeling nostalgic (LP: #839257)
  * softwarecenter/ui/gtk3/views/appdetailsview_gtk.py:
    - fix incorrect ellipsize for title and summary in the
      details view (LP: #842271)
  * softwarecenter/ui/gtk3/panes/availablepane.py,
    softwarecenter/ui/gtk3/session/viewmanager.py:
    - hide the search field when in the purchase
      view (LP: #844883)
  * softwarecenter/ui/gtk3/views/catview_gtk.py:
    - don't create the what's new panel if we don't have the
      corresponding category (LP: #835129)
  * softwarecenter/ui/gtk3/panes/installedpane.py:
    - fix crash in rebuild_categorised_view while viewing
      installed items (LP: #834260)
  * test/gtk3/test_catview.py,
    test/gtk3/test_panes.py,
    test/test_addons.py,
    test/test_package_info.py:
    - fix unit tests
  * setup.py:
    - fix build error when merging authors list
  * merged lp:~gary-lasker/software-center/pyflakes-fixes, no
    user visible changes, only code cleanup
  * po/software-center.pot:
    - refresh .pot file

  [ Matthew McGowan ]
  * data/ui/gtk3/css/softwarecenter.css,
    softwarecenter/ui/gtk3/views/appdetailsview_gtk.py:
    - fix grey addon label, only pkgname should be grey
      (LP: #838607)
  * softwarecenter/ui/gtk3/widgets/description.py,
    softwarecenter/utils.py,
    test/test_description_norm.py:
    - description formatting improvements, update unit test
  * data/ui/gtk3/css/softwarecenter.css,
    softwarecenter/ui/gtk3/widgets/cellrenderers.py:
    - use css to set border-radius of cellrenderer button
  * softwarecenter/ui/gtk3/views/appview.py:
    - disable appcount display at the bottom of list views
      for now to allow keyboard scrolling to work (LP: #830258)
  * lp:~mmcg069/software-center/lobby-tweaks:
    - restore tile borders but disable the checkerboard
      rendering, color tweaks and other improvements to the
      title area visuals
  * merge lp:~mmcg069/software-center/image-data-cleanup:
    - cleanup unused image files (LP: #839736)
  * softwarecenter/ui/gtk3/panes/softwarepane.py:
    - fix doubled search results (LP: #840235)
  * softwarecenter/ui/gtk3/app.py:
    - fix "Copy Web Link" feature (LP: #830291)

  [ Andrea Cimitan ]
  * softwarecenter/ui/gtk3/widgets/symbolic_icons.py:
    - Fix blurriness of toolbar icons, reduce shadow alpha level

  [ Gabor Kelemen ]
  * po/POTFILES.in:
    - additional i18n fixes (LP: #836346)

  [ Kiwinote ]
  * remove the old webkit ui
  * remove the need for dummy-screenshot-ubuntu.png (LP: #837223)
  * data/ui/gtk3/SoftwareCenter.ui,
    softwarecenter/ui/gtk3/app.py:
    - make all the accelerators work again (LP: #640426, LP: #660050,
      LP: #828233, LP: #830238, LP: #834988, LP: #843682)
      also fixes (LP: #823094, LP: #837062)
  * softwarecenter/db/appfilter.py,
    softwarecenter/ui/...