[otrs] Owner not notified on ticket merge

Running OTRS 3.3.2. When a new ticket is merged into an existing ticket, the ticket owner is not notified: - the status does not change - there is no 'star' in front of the new ticket action - no e-mail is sent How to reproduce: - have an existing ticket in a pending status, with a different agent who is the owner - have a new ticket without owner - open the new ticket and merge it with the existing ticket - you are taken to the existing ticket and see the merge action - the agent who owns the existing ticket does not see that it was updated, only when he opens it, he may discover the new ticket action Because of this, an important update was not seen in time by the ticket owner. How can this be changed?