[imp] imp and virtual hosts

[ianux]

I just install IMP 3.2.1 and there is a strange thing...
in fact, I'm running two instances of Horde
one is in /usr/local/apache/htdocs/horde and the other in
/usr/local/apache/horde-ssl
in fact, horde-ssl is the result of cp -r horde horde-ssl, so this two
directories are strictly the same
I have configured Apache so that http://localhost links to
http://localhost/horde/imp, and https://localhost links to
http://localhost/horde-ssl/imp
The strange thing is that when I go into http, my browser show me the
login screen with the URL http://localhost/ and the favicon of Horde (a
house), and when I go into https, my browser show
https://localhost/login.php?IMP=93aa19acc2dec33c3b0d42fa2cdde312 with
the favicon of IMP (an envelope)
But the content of this two site is supposed to be the same and behave
the same manner !
is this a matter of Apache configuration ?