[imp] autologin creating new sessions mid-session

[liamr at umich.edu]

>> It would be extremely helpful if you could narrow down a change that caused
>> this. I'm not aware of any big changes in authentication, so I'm a 
>> little at a loss for where to start looking.
>
> I'm not sure.  It didn't do this in the beta, and I'm using the same
> configuration on our end.  I've tried switching to the native php session
> handler and that didn't work.  I tried turning off hordeauth passthru
> authentication in imp/config/servers.php, and that didn't work.  In each
> case, every time you switch applications, you get a new sessionID - even
> if you go back to an application you were already using.

In OS X, The "new sessionID mid-session" problem is showing up in our
installation w/ Mozilla 1.7 and Firefox 1.0, but not on Safari or in IE 5
(though the layout in IE 5 for OS X is really unpleasant looking in RC1.. the
beta looks ok tho.)

On WinXP, IE5 works fine, but Mozilla, Firefox, and Netscape 7.1 all 
exhibit the
problem.

ideas?