Fix for blue dot on Mail emails

You can easily set the Mail swipe-gesture options in iPad settings - choosing your preferred actions from those available:

Settings > Apps > Mail > Swipe Options - tap Swipe Left or Swipe Right and select from the list of options

You can also swipe the mail in your inbox to the right and let it go, to do that automatically, without tapping on the "Read" button. Swiping to the right will mark a read mail is as Unread again.