Custom theme per each forum doesn't work like it should

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Log in as admin
2. Change some forums theme different from default
3. Go to this forum after saving changes

What is the expected output? What do you see instead?
Should change theme. You must hop different places in this forum (reply -> 
back to the forum -> new reply) before it changes to selected theme.

What version of the product are you using? On what operating system?
Revision 14

Please provide any additional information below.
When logged out, no theme changes!!!
Probably related with cookies.

Original issue reported on code.google.com by [email protected] on 21 Feb 2010 at 12:43