Ticket toggles open/close when pressing enter while focus is on email

To reproduce:

  1. Create a new anonymous ticket
  2. Click in the email field, so that it gets focus
  3. Press enter

Expected result: nothing changes Actual result: the ticket is marked as Closed

  1. Repeat 2 and 3, and the ticket gets marked as Open again. The field toggles every time.

(from redmine: created on 2014-05-12, closed on 2014-05-14)