BK, it's not quite like that. Normally Firefox asks how to treat cookies (I have Always Ask checked) when it doesn't have specific site instructions. (Eg, if I delete the cookies or a new site.)

Then it gives 4 choices: Block, Allow, Allow for Session and Forget It And Go Rollerblade Over To A Bar. I choose the last one now.

BUT, for Mudcat and several other sites it just don't ask. I have to login and Firefox always records it as a Session Cookie. It does not get into cookies.txt at all. I even set Firefox Exceptions to Always Allow Mudcat. No use.

So yes, they reappear next time I login.