Null exception in ZXing.Mobile.ZXingScannnerControl.OnTap

[brewvn]

I sometime got this Null exception in my app. I fixed this issue by adding a check of _reader variable:
protected override void OnTap(System.Windows.Input.GestureEventArgs e)
{
base.OnTap(e);
if (_reader != null)
{
_reader.Focus();
}
}
Thanks for greate project!