[imp] Imp 4.2 weirdness

[Kevin Konowalec]

So we put horde 3.2/imp 4.2 into production.  It ran fine for an hour  
or two... and then suddenly users were no longer able to access Imp.   
They'd just get a blank screen where the inbox should be.  Logging  
into Horde was fine - you'd get the sidebar with the options and what  
not (no Imp though) and the "problem report" button at the top (and  
believe me... people used that one a LOT).

We reverted to the old cluster so we could test the new one further.   
I turned on debug logging and saw the following:

  User testtesttest at ualberta.ca does not have READ permission for imp

I immediately assumed it was a database error of some kind.  But then  
one of my colleagues found the following snippet in /horde/lib/Horde/ 
Registry.php line 818:

* If permissions checking is requested, return an error if the
* current user does not have read perms to the application being
* loaded. We allow access:
*
* - To all admins.
* - To all authenticated users if no permission is set on $app.
* - To anyone who is allowed by an explicit ACL on $app. */

To which I responded "Ah HAH!".  So I looked in the permissions setup,  
where I had added two permissions settings (max_recipients and  
max_timelimit).  Sure enough in the Mail (imp) permission for all  
authenticated users, all 4 checkboxes (show, read, edit, delete) were  
unchecked.  I checked "read" and saved it and immediately things went  
back to normal.

So my questions are:

1)  Did this actually solve the problem or am I going to piss off my  
users again when I put it back into production tomorrow morning?
2)  Why would users be able to work normally for so long before horde  
decided it wanted to enforce the permissions?  Should they not have  
been failing right from the get-go?
3)  What are all the various permissions for (show, read, edit,  
delete)?  Which ones should be set?

Thanks

K