I am using Ubuntu 11.10 Unity with activated default theme Ambiance. My problem here is that there are no shadows visible for any window. I tried to enable them using gconf-edit, but that did not work for me.
After googling a little more, I found out, that these Compiz values get overridden or are ignored by Unity. So I tried to edit the file /usr/share/themes/Ambiance/metacity-1/metacity-theme-1.xml, but that did not help either.
Any suggestions are welcome, because my desktop looks rather messy with a few windows open. It's hard to distinguish between windows without visible shadows.