What might be happening here is that when you add the .ics
from disk to Outlook, Outlook doen't have to check any permissions to modify the file. Now when you added from internet, that means that the .ics
belongs to a calendar provider, which generally implement the ACL protocol. This protocol specify some methods to check the permission when a client want to read/modify a calendar.
So when you add the .ics
you have to specify an URL
that is the container of the file (generally this URL
is gonna be the a Calendar Collection that belongs to the CALDAV:calendar-home-set
), so the client sends a Profind
request to the server asking for the DAV:current-user-privilege-set
and the definition of this property is:
DAV:current-user-privilege-set is a protected property containing the
exact set of privileges (as computed by the server) granted to the
currently authenticated HTTP user. Aggregate privileges and their
contained privileges are listed. A user-agent can use the value of
this property to adjust its user interface to make actions
inaccessible (e.g., by graying out a menu item or button) for which
the current principal does not have permission. This property is
also useful for determining what operations the current principal can
perform, without having to actually execute an operation.
So after this, Outlook knows that the current principal doesn't have any permission to perform any action on this calendar resource and it just doesn't show any action for the file.
Hope it helps.