Changes have been made in Git (master):

commit fa30a52c1c6d5c95c4f123debe9e799f5dd824c1
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Wed Apr 2 19:15:23 2014 -0400

     The prettyautocompleter should not propagate KEY_RETURN presses.

     Should act like anyother textarea (since that what it looks like from
     the user's point of view). As a bonus, fixes Bug: 12932.

  framework/Core/js/prettyautocomplete.js |    4 ++--
  1 files changed, 2 insertions(+), 2 deletions(-)

http://github.com/horde/horde/commit/fa30a52c1c6d5c95c4f123debe9e799f5dd824c1

Sure. That was my point.

It does, at least in my side. With my patch, hitting ENTER before 
typing a comma the input field disappear, the tag/attendee is included 
in the list ( I can even see the freebusy info of that last attendee) 
and then clicking "save event" button, last tag/attendee is saved with 
the event (and invitations are properly sent).

Anyway, I don't want to put the focus on my patch, probably it is only 
a fast/dirty way to prevent this issue (i insist, it works for me) and 
I agree with you that it breaks the common input behaviour.

Let's put the focus in the issue that hitting enter before typing a 
comma doesn't save the last tag/attendee. It is very frustrating 
specially with attendees, because invitation is not sent to the last 
attendee if you forget to put a comma or blur the input.

That's what I'm saying. It DOESN'T fix this issue. If you are still 
typing the tag name before typing a comma (and thus still inside the 
hidden text field), hitting ENTER still saves the event - and without 
the tag being saved entered

You are right, the most important issue here is that the last   
tag/attendee is not saved. My patch doesn't fix that, but it was a way 
to prevent this "side effect". With my patch, hitting RETURN doesn't 
save the event but finish editing mode of tag/attendees, so the last 
tag/attendee is properly included in the final list.

I agree with you when you say that all fields should behave the same 
way, but at least this issue should be resolved.

Thanks

I disagree. I think the bigger issue here is that hitting RETURN 
before you type a comma will save the event WITHOUT the tag. Your 
patch doesn't fix this.

Otherwise, I think the tag field should be treated just like any other 
field in the form, and require a TAB out of it, or RETURN to save.

When you are editing tags or attendees of an event (i mean, the focus 
is in a tag input or attendee input) and then you press ENTER key, the 
event is saved and the tag or attendee where you was before is not 
saved, which is annoying because some users think that pressing ENTER 
in last element is the proper way to finish tag/attendee editing.

I suggest a blur action instead of saving event only applied if you 
are in that kind of inputs. I attach a little patch of kronolith.js to 
do so.