When playing Bridge on BBO, you can inadvertantly make the wrong bid.

There is an UNDO option available, however, this this has been turned off, as many are not ONLY using for a slip of a clumsy finger, but for a Change of Mind.

To guard against 'misclicks' you should change the options under settings to 'Confirm Bids'  this means you will have to OK the bid before it is made - there is no going back.