Use Watcher List For Target Versions When List Is Long
The "Add watcher" feature now provides a search field and check boxes, this UI would be extremely useful when you have a lot of target versions (such as Redmine has right now).
Additionally, being able to filter that check box list by status (open/closed) would be extremely useful, allowing the user to filter only open/closed target versions and select from that list.
This also meets the needs of the related tickets.
How flexible is the helper (I think it's a helper...) used for the watchers list?