How to disable transparency in Opera?

I've just installed the latest desktop build of Opera, and since it has transparency support for Windows 7, it looks horrible on XP. Is there anyway to disable the transparency of Opera so that it is normal again?

I don't have Windows 7 but wonder if this page may help you

http://my.opera.com/portalnews/blog/2010/03/27/take-full-advantage-of-windows-7-with-opera

I guess, your best shot (IMO) is to try a different theme?

ishan_rulz is absolutely correct. Also as you upgrade Opera you should be able to keep your opacity preferences by maintaining the skin you like.