private static void AdjustCarretIndexOrMoveToNeighbour(TextBox current, TextBox neighbour)
{
//if the current is near the end move to neighbour
if (current.CaretIndex == 1 && neighbour != null)
neighbour.Focus();
//if the carrot is in the first index move the caret one index
else if (current.CaretIndex == 0)
current.CaretIndex++;
}