Gmail's new Undo Send button in case you regret your last email

One of the most popular experimental features to come from Gmail Labs is 'Undo Send'. After a long stint as an experimental feature, it is now being rolled out as an official Gmail feature on the web.For those who have been using the Labs version of Undo Send, the setting for the feature will be enabled by default. Others will have to go and enable the feature under Gmail settings.Undo Send became one of the most popular features to come from the Labs. We’ve all been through those moments of regret when we've clicked on the Send button and then realised that the mail has some error (or has something in it you might not have wanted to actually say).The Undo button would exist for a few seconds from the time you hit Send, which was enough time for most users to prevent the message ever leaving their mailbox. Now, it lets you select a time frame of delay between 5 to 30 seconds.It should be noted that the Undo Send feature was seen recently seen in Inbox by Gmail.