How can I detect the dragging operation of the splitter?

//This code demonstrates how to add the TabSplitter and TabSplitterItem:
<Window x:Class="TabsplitterSample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <syncfusion:TabSplitter Name="tabsplitter">
            <syncfusion:TabSplitterItem>
                <syncfusion:TabSplitterItem.TopPanelItems>
                    <syncfusion:SplitterPage Header="Tab1"/>
                </syncfusion:TabSplitterItem.TopPanelItems>
                <syncfusion:TabSplitterItem.BottomPanelItems>
                     <syncfusion:SplitterPage Header="Tab2"/>
                </syncfusion:TabSplitterItem.BottomPanelItems>
            </syncfusion:TabSplitterItem>
        </syncfusion:TabSplitter>
    </Grid>
</Window>

//This code demonstrates how to access the events of DragStarted and DragCompleted for the splitter:
using Syncfusion.Windows.Tools.Controls;
namespace TabsplitterSample
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            tabsplitter.Loaded += new RoutedEventHandler(tabsplitter_Loaded);
        }
        private bool TabSplitterDragging;
        void tabsplitter_Loaded(object sender, RoutedEventArgs e)
        {
// This code shows that the splitter has been taken from the Template of the TabSplitter
           CustomGridSplitter splitter = tabsplitter.Template.FindName("PART_Splitter", tabsplitter) as CustomGridSplitter;
           if (splitter != null)
           {
// This code shows the DragStarted and DragCompleted Events of the splitter
               splitter.DragStarted += new System.Windows.Controls.Primitives.DragStartedEventHandler(splitter_DragStarted);
               splitter.DragCompleted += new System.Windows.Controls.Primitives.DragCompletedEventHandler(splitter_DragCompleted);
           }
        }
        void splitter_DragCompleted(object sender, System.Windows.Controls.Primitives.DragCompletedEventArgs e)
        {
            TabSplitterDragging = false;
        }
        void splitter_DragStarted(object sender, System.Windows.Controls.Primitives.DragStartedEventArgs e)
        {
            TabSplitterDragging = true;
        }
    }
}