[squid-users] fail over to parent proxy doesn't work for https

Hi,

As mentioned in help,
By combining nonhierarchical_direct off and prefer_direct on you can
set up Squid to use a parent as a backup path if going direct fails.
I did the following configuration to use parent proxy ,

cache_peer_access proxy_parent.test.com allow all
nonhierarchical_direct off
prefer_direct on
connect_timeout 5 seconds

It works fine for http GET request. But doesn't work for https
(CONNECT) request. https access will always try direct.
Any idea about that?

I tested on squid 2.6 stable and 3.0 stable, both of them doesn't work

-- 
Leo Tao