==== Required information ====
- iRedMail version (check /etc/iredmail-release): iRedMail-0.9.5-1
- Linux/BSD distribution name and version: Ubuntu 14.04.4 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): Windows 2003 Active Directory
- Web server (Apache or Nginx): Apache/2.4.7 (Ubuntu)
- Manage mail accounts with iRedAdmin-Pro? No
- Related log if you're reporting an issue: as follows...
====

Hello!
    Sorry to post this issue here, but Sogo free support is a little bit limited. Here we go:

As I understand (correct me if I am wrong, please) the idea of the Delegation functionality is to enable one user to have the access to another user's identity (in a very basic explantion). For example: If user1 delegates rights to user2, user2 will be able to send e-mail using user1's identity, all user2 has to do is to compose a new mail and choose user1's e-mail address from the dropdown list in the "From" field. Is it correct?

Well, the ideia is very nice, if it worked and if I am right.
In a iRedmail clean install, using LDAP support (no AD integration, just the native LDAP already provided by the typical iRedMail installation), if I delegate the rights from user1 to user2, user1 doesn't appear as available in the "From" dropdown, the only identity is user2's himself.
The delegation was made using Sogo, while the absence happend in Sogo and Roundcube.

Again, I don't know what log to look for. I've looked at mail.log but there is no clues of what maybe happening.

If you could please help me to solve it or to give some clues, I'd be very thankful.

I didn't post any log here because there is so many things in my mail.log that I'd rather to ask you what you need from this log - of course that if the full log is needed, I'll post here gladly.

Thank you.