My window manager resets to default install settings.
This posted from another discussion:
As a short term work around I simply click on the Compiz Settings Manager icon and click the 'Reload Window Manager'.
This sets my window theme back to my preferred options.
To me this would suggest that something is checking the system now and then for some reason and resetting the window manager to the original install settings.
Although, I quite like the original I can't always get the colours I need to work in for certain environments as some options can be difficult for me to read with the font and background colours set as they are.
So I don't know if this helps but, it is something to do with the default install setting perhaps...