I posted a comment in chat that had an obvious spelling error, and realized that I couldn't edit it. No big deal, just post the correction in another comment...but then I saw that I had yet another error (I know, I can barely speak English), and had to post another comment.
SE chat gives a time limit to edit your comments (I think either 2 or 5 minutes, and mods might me able to edit them whenever). How should we handle comment edits? A time limit? No limit at all? Possibility of reading the original comment to avoid misunderstandings and/or arguments? An edit history, in other words.
update Jul 2020: we've upped the edit limit considerably:
@@@ answer 1389
We have implemented this with a 5-minute limit per [Paul's suggestion](https://topanswers.xyz/meta?q=14#a4):
> A five-minute time limit on chat message edits seems reasonable to me.
Click the new button that appears to the right of your message on hover:
!['edit chat' button](/image?hash=7f0efc8afbbb404eea34b3d5cd8a85c81d04586d55e85e665821608ff75bf7e9)
Alternatively, the 'up' arrow is a shortcut to editing your latest chat message (this only works if the chat input box is empty).
A five-minute time limit on chat message edits seems reasonable to me.
The two-minute limit on SE chat is a bit too short.
Allowing edits on all messages visible in the current window sounds like an attractive alternative, but it might be misused.