WPF tab order with custom controls?

Question

I have a WPF page that contains several out of the box controls with the tab order set.

I have a custom control (NumericSpinner) that contains: border/grid/text box/

Answer 1

Raul answered the primary issue - being able to tab into the text box of a custom control. The secondary problem was not being able to tab out of the text box.

The issue with this control was that its textbox contains a keypress handler:

PreviewKeyDown="valueText_PreviewKeyDown"

The handler only allows certain keys to be pressed within the textbox:

/// 

/// Since this event handler traps keystrokes within the control, in order to facilitate tabbing order, allowing the 
/// tab key press must be enabled
/// 
/// 
/// 
private void valueText_PreviewKeyDown(object sender, KeyEventArgs e)
{ 
    KeyConverter converter = new KeyConverter();
    string key = converter.ConvertToString(e.Key);
    int index = ((TextBox)sender).CaretIndex;
    if (key != null)
    {
        if (AllowNegativeValues && (e.Key == Key.Subtract || e.Key == Key.OemMinus))
        {
            e.Handled = (valueText.Text.Contains('-') || index > 0) == true;
        }
        else if (AllowDecimal && (e.Key == Key.OemPeriod || e.Key == Key.Decimal))
        {
            e.Handled = valueText.Text.Contains('.') == true;
        }
        else
            e.Handled = ((((e.Key >= Key.D0) && (e.Key <= Key.D9) && (e.KeyboardDevice.Modifiers != ModifierKeys.Shift))
                            || ((e.Key >= Key.NumPad0) && (e.Key <= Key.NumPad9) && (e.KeyboardDevice.Modifiers != ModifierKeys.Shift))
                            || e.Key == Key.Left || e.Key == Key.Right
                            || e.Key == Key.Back || e.Key == Key.Delete 
                            || e.Key == Key.Tab) == false);             
    }
    else
        e.Handled = true;
}

I simply had to add the allowable TAB keystroke and the custom control works fine:

e.Key == Key.Tab