How to handle focus events of the RibbonTextBox in WPF Ribbon control?

<syncfusion:RibbonWindow x:Class="Ribbon_131602.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525"
        xmlns:local="clr-namespace:Ribbon_131602"
        syncfusion:SkinStorage.VisualStyle="Metro"
        xmlns:syncfusion="http://schemas.syncfusion.com/wpf">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <syncfusion:Ribbon Name="MyRibbon" BackStageCornerImageVisibility="Collapsed"
                        EnableMoreCommands="False">            
            <syncfusion:RibbonTab Caption="TextFocus" syncfusion:Ribbon.KeyTip="E">
                <syncfusion:RibbonBar Header="FocusBar">
                    <syncfusion:RibbonTextBox Text="Simple text" x:Name="Text1" />
                    <syncfusion:RibbonTextBox Text="Focus Text" x:Name="Text2" GotKeyboardFocus="Text2_GotKeyboardFocus" PreviewMouseLeftButtonDown="Text2_PreviewMouseLeftButtonDown"/>
                    <syncfusion:RibbonTextBox Text="Simple text" x:Name="Text3" />
                </syncfusion:RibbonBar>
            </syncfusion:RibbonTab>
        </syncfusion:Ribbon>
        <Grid Grid.Row="1">
            <RichTextBox Margin="12">
                <FlowDocument>
                    <Paragraph>
                        In this sample, we have added 3 RibbonTextBox to the TextFocus RibbonTab. The second TextBox has the Text to be selected when it receives focus.
                    </Paragraph> 
                </FlowDocument>
            </RichTextBox>
        </Grid>
    </Grid>
</syncfusion:RibbonWindow>

public partial class MainWindow : RibbonWindow
{
    public MainWindow()
    {
        InitializeComponent();
    }
    private void Text2_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
    {
        if (Text2 != null && !string.IsNullOrEmpty(Text2.Text))
           Text2.SelectAll();
    }
    private void Text2_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        if(Text2!=null)
        {
           if(!Text2.IsKeyboardFocusWithin)
           {
              e.Handled = true;
              Text2.Focus();
           }
        }
    }
}