How to restrict the dockability of child window to client area in DockingManager

      <syncfusion:DockingManager x:Name="dockingmanager">
            <syncfusion:DockingManager.ClientControl>
                <ContentControl Name="ClientArea" syncfusion:DockingManager.DesiredWidthInDockedMode="700" syncfusion:DockingManager.SideInDockedMode="Left"/>
            </syncfusion:DockingManager.ClientControl>
   <ContentControl x:Name="Media" syncfusion:DockingManager.Header="Dock1" syncfusion:DockingManager.SideInDockedMode= "Bottom" />
   <ContentControl x:Name="Timeline" syncfusion:DockingManager.Header="Dock2"  syncfusion:DockingManager.SideInDockedMode="Bottom" />
   
   <ContentControl syncfusion:DockingManager.Header="Dock3" syncfusion:DockingManager.DesiredWidthInDockedMode="300" syncfusion:DockingManager.SideInDockedMode="Right"
    Name="Properties"/>
   <ContentControl x:Name="playlist" syncfusion:DockingManager.Header="Dock4" syncfusion:DockingManager.DesiredWidthInDockedMode="240"  syncfusion:DockingManager.SideInDockedMode= "Tabbed" 
                 syncfusion:DockingManager.TargetNameInDockedMode="Properties" />            
  </syncfusion:DockingManager>
 

       public partial class MainWindow : Window
 {
        public MainWindow()
        {
            InitializeComponent();
           
            dockingmanager.PreviewMouseDown += Dockingmanager_PreviewMouseDown;
            dockingmanager.PreviewMouseUp += Dockingmanager_PreviewMouseUp;
            dockingmanager.PreviewMouseMove += Dockingmanager_PreviewMouseMove;            
        }       
       
        bool isMouseDown = false;
        bool isDragging = false;
        Point mouseDownPoint;
        Point mousePoint;
        DockedElementTabbedHost draggedelement = null;
        List<FrameworkElement> tabs = null;
        private void Dockingmanager_PreviewMouseUp(object sender, MouseButtonEventArgs e)
        {
            if (draggedelement != null && tabs != null)
            {
                foreach(var element in tabs)
                {
                    if (DockingManager.GetDockAbility(element as FrameworkElement) == DockAbility.None)
                        DockingManager.SetState(element as FrameworkElement, DockState.Dock);
                    DockingManager.SetDockAbility(element as FrameworkElement, DockAbility.All);
                }                
            }
 
            isMouseDown = false;
            isDragging = false;                      
            tabs = null;
            draggedelement = null;
        }
 
        internal bool IsPointInsideElement(UIElement element)
        {
            Point pt = Mouse.GetPosition(element);
            Point point =  element.TranslatePoint(new Point(0, 0), this.dockingmanager);
 
            return pt.X > -5 && pt.Y > -5 && pt.X < point.X + element.RenderSize.Width && pt.Y < point.Y + element.RenderSize.Height;
        }
       
        private void Dockingmanager_PreviewMouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseDown)
            {
                mousePoint = e.GetPosition(e.OriginalSource as IInputElement);
                draggedelement = VisualUtils.FindAncestor(dockingmanager.ActiveWindow, typeof(DockedElementTabbedHost)) as DockedElementTabbedHost;
 
                if (Math.Abs(mousePoint.X - mouseDownPoint.X) > 4 || Math.Abs(mousePoint.Y - mouseDownPoint.Y) > 4)
                {
                    isDragging = true;
                }
 
                if (isDragging)
                {
                    if (draggedelement != null && draggedelement.TabChildren != null && draggedelement.TabChildren.Count > 0)
                    {
                        tabs = new List<FrameworkElement>(draggedelement.TabChildren);
                        if (tabs != null)
                        {
                            if (IsPointInsideElement(ClientArea))
                            {                               
                                foreach (var element in tabs)
                                {
                                    DockingManager.SetDockAbility(element as FrameworkElement, DockAbility.None);
                                }
 
                            }
                            else if (!IsPointInsideElement(ClientArea))
                            {                                
                                foreach (var element in tabs)
                                {
                                    DockingManager.SetDockAbility(element as FrameworkElement, DockAbility.All);
                                }
                            }
                        }
                    }
                }
            }
        }
             
        private void Dockingmanager_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            isMouseDown = true;            
            mouseDownPoint = e.GetPosition(e.OriginalSource as IInputElement);
        }
    }