Permissions strangeness on shared calendars

[gkra]

I'm discovering that permissions are a bit odd for shared calendars.

As an example, if I do

zmmailbox -z -m <myaccount>@<mydomain> gfg /Calendar

I see:

Permissions    Type  Display
-----------  ------  -------
          r   group  readonlygroup@<mydomain>
          r  public
    rwidxap   group  admingroup@<mydomain>

Members of the admin group cannot modify my calendar.

If I change the ordering of the permissions (i.e., delete the 'r' perms, and then re-add them) so that they look like this:

Permissions    Type  Display
-----------  ------  -------
    rwidxap   group  admingroup@<mydomain>
          r   group  readonlygroup@<mydomain>
          r  public

Then everything works the way it's supposed to. This just feels incredibly broken to me. Isn't Zimbra simply ORing matching permissions together to come up with the final permission set, or is it it stupidly doing a "first match wins" with permissions?