[horde] problem to share calendar/addressbook

[Philip Steeman]

Hello,
I installed the latest stable versions of horde/imp/...
It is indeed very good, but I have one problem:

When I "Let a Horde application handle authentication (IMP)" it is 
impossible to edit the permissions for a user to share my calendar.
All I can see is a listbox with 'Select a user to add' (with no users in 
the listbox).

When I choose for "IMAP authentication" I get a textfield where I can 
insert a username, and all works fine.

But I prefer to let IMP handle the authentication, otherwise I have to 
log in twice.

Can someone help me?

Philip