After upgrade to Ubuntu 12.10 writer disappeared so I installed it via software center but now my Writer look like this:
How to revert to default theme so it looks exact like rest of system. I'm using Ambience theme.
You did not install the full LibreOffice suite. In particular you are missing libreoffice-gnome (and libreoffice-gtk, but that will be installed by libreoffice-gnome). In general, it is a good idea to do a full:
to get the full suite (even the Ubuntu default install contains only a partial installation).