Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5
NoScript 1.9.9.14, no other extensions, default theme.
Steps to reproduce:
1) Change the default settings as follows:
- Temporarily allow top-level sites
 - Full addresses only
 - (under Contextual menu, which is not selected)
 - Base 2nd level Domains
 - Full Domains
 - Full Addresses
 
3) Click Allow social.microsoft.com
4) Click Forbid social.microsoft.com
Expected result: social.microsoft.com is removed from the whitelist and not marked untrusted.
Actual result: social.microsoft.com is marked untrusted
The expected behavior happens if I uncheck Temporarily allow top-level sites and temporarily allow social.msdn.microsoft.com manually.