GTK theming: oxygen-gtk support broken

Hello,

Some time after my commits, which enabled almost fully correct
oxygen-gtk support (latest commit was on Jul 8 2012), this support was
broken. See screenshots at [1], [2], [3] and [4] for details.
Those who hacked on GTK theming support since Jul 8 2012, please have
a look at this. If you think it's oxygen-gtk which should be fixed,
not libreoffice, please report the particular problems to
https://bugs.kde.org (product=Oxygen, component=gtk2-engine). I'll be
happy to improve things on oxygen-gtk side.

Thanks,
Ruslan

[1] Edit field and combo button sizes mismatch: http://i.imgur.com/lnvfS.png
[2] Background gradient not rendered: http://i.imgur.com/lRPLY.png
[3] Text line entry clips text to the left too much http://i.imgur.com/sV10D.png
[4] Menu expansion arrows are clipped at top: http://i.imgur.com/Gn67Z.png