Add option: If owner for ticket exist -> lock option

[ArkadiyD]

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Title: HESK
Version: 2.2
Author:
Demo:
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Hallo, one more quastion:
A new ticket do not have owner. If I take ownership and this ticket is opened with another user, he also can take ownership, HESK do not ask question like "Do you want to change owner on this ticket".
If there is any option to add such function.
if ($owner >0) then... i can`t find the right place to add this.

Thank you!