New ‘undo send’ button will allow Gmail users to cancel a sent email – if they instantly regret it! This newly added feature by Google is easy to set up. Just click on the settings button in your Gmail account (the wheel icon towards the top of the right hand side) and then select general in the drop-down menu. Make sure you’re in the general settings tab. The Undo Send button is the tenth option down and you can set the cancellation period for 5,…