private void HandleDownClick(object sender, RoutedEventArgs routedEventArgs) { if (AcceptUpDownOnNull && Number == null) { _number.ToMaximum(); } else { _number.Decrease(); } TakeNumber(); _textBox.Text = _number.ToString(); if (NumberSelectionBehavior == NumberBoxSelection.OnFocusAndUpDown || NumberSelectionBehavior == NumberBoxSelection.OnUpDown) { SelectAll(); } }