UIButton fails to properly register touch in bottom region of iPhone screen

Question

I have an app with many different buttons arranged in a calculator like, square / rectangular format. It is actually extremely similar to the default iOS calculator. There a

Answer 1

answer of Lukas in swift and deselect highlighted

extension UIButton {

  public override func pointInside(point: CGPoint, withEvent event: UIEvent?) -> Bool {

    var inside = super.pointInside(point, withEvent: event)

    if inside != highlighted && event?.type == .Touches {
        highlighted = inside
    }

    return inside

  }

}