Add an indicator when some list item is being edited for other people to be able to see it
Jim Leff commented
Ideally this indicator would appear when an editor clicks to highlight - or double clicks (or types "ee") to edit - a list item that another editor currently has open for editing. When that previous editor closes or saves the item (whether or not he's made a change), the indicator would disappear.
the indicator should be red, or otherwise grab attention, so the user understands to show caution (re: potential data loss of concurrent edits).
Even better if the indicator could show WHICH user is currently editing.