How to float the Docking childrenManager in the BorderDragging mode?

<Window x:Class="DockWindow_Property.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 x:Name="Grid1">
        <syncfusion:DockingManager x:Name="Dock1"  DraggingType="BorderDragging"  >
        <ContentControl Name="Content1" syncfusion:DockingManager.Header="Dock1" ></ContentControl>
        <ContentControl Name="Content2" syncfusion:DockingManager.Header="Dock2"></ContentControl>
        <ContentControl Name="Content3" syncfusion:DockingManager.Header="Dock3"></ContentControl>
        </syncfusion:DockingManager>
        </Grid>
</Window>

using Syncfusion.Windows.Tools.Controls;
namespace DockWindow_Property
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml.
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            DockingManager DockingManager1 = new DockingManager();
            ContentControl content1 = new ContentControl();
            ContentControl content2 = new ContentControl();
            ContentControl content3 = new ContentControl();
            DockingManager.SetHeader(content1, "Dock1");
            DockingManager.SetHeader(content2, "Dock2");
            DockingManager.SetHeader(content3, "Dock3");
            DockingManager1.DraggingType = DraggingType.BorderDragging;
            DockingManager1.Children.Add(content1);
            DockingManager1.Children.Add(content2);
            DockingManager1.Children.Add(content3);
            Grid1.Children.Add(DockingManager1);
        } 
    }
}