Severe treeview performance regression (Gtk2 -> gtk3)

[Clemens Eisserer <linuxhippy gmail com>]

Hi,

Fedora16 comes with a gtk3 port of Audacious.
After updating I immediatly noticed how slow the playlist scrolls (a
quite ordinary TreeView with a few hundred lines),
when scrolling using the scrollwheel GTK3 barely keeps up, which
usually results in "afterscrolling" - on a Core2Duo with 2ghz / 4MB
cache.
GTK2's TreeView was not fast either (compared to e.g. Java's JTable),
but it didn't feel disturbing.

I hacked together a simple sample application which compiles under
gtk2 as well as gtk3: http://93.83.133.214/gtklist.c
Just maximize it (preferable on a large screen) and scroll with your
wheel - the gtk3 version should feel a lot slower.

Would be great if somebody could have a look at this regression.
I didn't file a bug-report, because usually bugzilla reports fade away
into legacy unnoticed.

Thank you in advance, Clemens