Notification that question has been edited or re-tagged while answering
Currently, if one is writing an answer to a question and someone else posts an answer, we get a banner notification on top. I'm not sure, but I think that the banner appears if you are vieweing the page even if not actively typing an answer (it may be that this only occurs if there has been some writing done in the answer box).
If an answer previously posted is edited while you are writing an answer (or while viewing), however, it seems that one does not get a notification. Is there any chance of adding such a notification (or changing the "an answer has been posted" banner to "an answer has been posted or modified")? Or would it cost too many resources to keep track of edits as well as new answers?