[GLLUG] Firefox Cookie Control

[Chick Tower]

I just discovered something slightly disturbing.  I usually use Firefox 
at on desktop PCs, and Slackware is only up to version 31.7.0esr.  I 
like to keep a tight rein on what cookies are set, with very few that 
aren't erased at the end of the session, if not blocked from the start. 
  However, I've noticed that sometimes after closing Firefox to erase 
those session cookies they are still there in a new session.  When I 
check the cookie exceptions that are set, some say "Allow first party 
only". I've never selected that, it's not even an option offered, and 
I've deleted or changed those exceptions, but they keep coming back.  It 
appears Yahoo! and Google know how to change the exceptions I put in 
Firefox!  There may be other websites that do this, but I haven't 
noticed any of the others I visit doing it.  At least they change them 
to "Allow first party only" and don't enable third-party cookies, but it 
still galls me that they're controlling my browser settings.

It bothers me that I can't block or make temporary cookies from 
accounts.google.com or ads.yahoo.com.  Other domains from Google and 
Yahoo! also do this, but they aren't as simple to remember and type as 
these two are.  I know I can delete them manually, which isn't 
difficult, but it's still annoying.  I don't want to block or erase all 
cookies, because some are useful (like the TV schedule), and some sites 
won't allow you to go forward without setting cookies.  It may be that 
Google and Yahoo! can ignore those settings, too.  I haven't tried any 
of the cookie-managing add-ons.  I do use Privoxy, so I could probably 
create some new rules or entries to stop this, and I suspect that would 
work since it's not part of any browser.  I'm not interested at this 
time in using another browser, and other common browsers might be 
similarly vulnerable, anyway.

Does anyone know of a setting or an add-on or a hack in about:config 
that will stop this behavior?  Has anyone else noticed it?  I searched 
on DuckDuckGo for "Allow first party only" and didn't find anything useful.
-- 

                                Chick