Facebook users can now edit a comment they’ve left on a news feed story or wall post by clicking the ‘x’ button within the first few seconds after posting the comment. Instead of deleting the comment as before, the ‘x’ button re-opens the comment input field and lets users edit the previously entered text.

This new feature should help users who’ve posted a long comment, but then immediately notice a typo or want to change the comment without having to delete it and re-type the whole thing.

Our initial tests show the time window in which edits are permitted to be about 12 seconds. After that, the only option is to delete the comment. Also, the Known Issues on Facebook Page that made the announcement mentioned that “if another person comments before you click the delete button, this edit option is no longer available.” The option is only available for comments, not initial wall or news feed posts.

A post’s author and other commenters will only receive a single Facebook notification for a comment that has been edited and reposted multiple times. However, if they have email notifications enabled, they’ll receive a copy of each version of the comment. This means that users still need to be careful about anything they post as a comment, as the edit option doesn’t ensure people won’t see the original.

Facebook comment editing is reminiscent of Gmail’s option “undo” feature that lets users retract an email within a few seconds of sending it. Facebook recently moved to a real-time commenting system in February, though comment edits don’t appear in real-time to other users. They’ll have to reload the page to see the updated version of a comment.

The purpose the feature is likely to encourage users to comment with more confidence, and to decrease the number of comment deletions. Long, thoughtful comments drive additional engagement, so it’s in Facebook’s interest to prevent situations where users delete comments rather than re-type them in order to fix a typo or insert a content change.