Last modified: 2013-05-18 13:51:17 UTC
Try typing non-ASCII characters in the VisualEditor edit summary field. For example, just type the Russian letter ΠΆ continuously. Towards the end it won't stop at 0, but at -1. Example screenshot from the Hebrew Wikipedia: http://j.mp/ZoQKX6 . This should be handled in a cleaner way. Either disallow typing anything that would go beyond zero, or allow all text to go beyond zero, as in Twitter or MoodBar.
Fixed in https://gerrit.wikimedia.org/r/#/c/64342/ To clarify, we aren't letting people go over the limit, we just aren't updating the counter after keyup. (If you get to -1 then press an arrow key, you'll see you're actually under the limit).
Merged; will go out with wmf5.