Currently, when creating or editing a tracker item and submitting this change, the user does not get any feedback that the submission is in progress if the server response is slow for some reason.
This sometimes leads to users clicking "submit" many times while the server is processing the request. This causes the same update to be posted many times, leading to an equal amount of mail notifications to each user. With a large project with many users subscribing to tracker notifications, this seems to be able to cause stability issues on the server and should be avoided.

I suggest that after pressing "submit" once, the button should be greyed out until the server has processed the ongoing request.