No this has been always in V5, we now just added the hint. plz let me try to explain we are forced to do this.
We do the content filtering prior squid stores the content in its cache.
Assume you now have two different profiles, one for 'Sales' and one for the 'Development' or one for 'Kids' and one for 'Adults'.
Now if you are surfing the 'Adult' Profile, all your Content gets stored in the cache. If now your kids access the same pages, squid would deliver them out of the cache without validating it against the content filter.
In order to prevent this, we automatically disable caching of request as soon as you enable the content filter.
I know that this is not very satisfying, but as squid is not capable of adding addtitional information to its cached objects, something like 'profile_name', we can not make sure that the content squid woudl deliver to the client would match his content filter profile.
There are plans to improve this behavior in the future.
Why? In ASL 4 you can just configure one Surf protection profile, which is enough from my point of view. Disabling the cache is a very bad solution. Why are you using a proxy? In my case to speed up the Internet browsing.
To install a proxy without caching makes no sense in a larger company.
