New Post: Inheriting from Polygon Type

Hello;
i'm trying to define my own Polygon implementation, adding an inernal marker that will add Tool Tip functionnality, however i faced two problems:

first , the GoogleMarker with image type None do not render (value of Bitmap can not be null).
second , the marker when set with some image, do not render in it's position.

<Serializable>
Public Class GLPolygonMarker
    Inherits GMap.NET.WindowsForms.GMapPolygon
    Implements ISerializable, IGLCustomMarker

    'Ctor:
    Public Sub New(points As List(Of GMap.NET.PointLatLng), Optional name As String = "Polygone")
        MyBase.New(points, name)
        If points Is Nothing OrElse points.Count = 0 Then
            Throw New ArgumentException("List Of Points Emty or Missing", "Points")
        End If
        Me.IsHitTestVisible = False
        _Type = GLCustomMarkerType.Polygon
        _Id = "S" & DateTime.Now.ToUniqueId()
        Me.Color = New GLSerialColor(Drawing.Color.Azure) With {.Alpha = 100}
        Me.Border = New GLSerialPen(Drawing.Color.DarkBlue, 1, Drawing2D.DashStyle.Solid)
        _TTMarker = New GMap.NET.WindowsForms.Markers.GMarkerGoogle(MyBase.Points.Item(0), GMap.NET.WindowsForms.Markers.GMarkerGoogleType.blue_small)
    End Sub

    'Id :
    Private _Id As String
    Public ReadOnly Property Id As String Implements IGLCustomMarker.Id
        Get
            Return _Id
        End Get
    End Property
    'Type:
    Private _Type As GLCustomMarkerType
    Public ReadOnly Property Type As GLCustomMarkerType Implements IGLCustomMarker.Type
        Get
            Return _Type
        End Get
    End Property
    'Name :
    Public Property PName As String Implements IGLCustomMarker.Name
        Get
            Return Me.Name
        End Get
        Set(value As String)
            If String.IsNullOrWhiteSpace(value) = False Then
                Me.Name = value
            End If
        End Set
    End Property
    'Pen:
    Private _Border As GLSerialPen
    Public Property Border As GLSerialPen Implements IGLCustomMarker.Border
        Get
            Return _Border
        End Get
        Set(value As GLSerialPen)
            _Border = value
            Me.Stroke = value.ToDotNetPen
        End Set
    End Property
    'Color:
    Private _Color As GLSerialColor
    Public Property Color As GLSerialColor Implements IGLCustomMarker.Color
        Get
            Return _Color
        End Get
        Set(value As GLSerialColor)
            _Color = value
            Me.Fill = New SolidBrush(_Color.ToDotNetColor)
        End Set
    End Property

    'Tooltip:
    Private _TTMarker As GMap.NET.WindowsForms.Markers.GMarkerGoogle
    Public Property TTText As String Implements IGLCustomMarker.TTText
        Get
            Return _TTMarker.ToolTipText
        End Get
        Set(value As String)
            _TTMarker.ToolTipText = value
        End Set
    End Property

    Public Property TTMode As GMap.NET.WindowsForms.MarkerTooltipMode Implements IGLCustomMarker.TTMode
        Get
            Return _TTMarker.ToolTipMode
        End Get
        Set(value As GMap.NET.WindowsForms.MarkerTooltipMode)
            _TTMarker.ToolTipMode = value
        End Set
    End Property

    'Drawing:
    Public Overrides Sub OnRender(g As Graphics)
        MyBase.OnRender(g)
        _TTMarker.OnRender(g)
    End Sub


    'Serialization:
    Public Overloads Sub GetObjectData(info As SerializationInfo, context As StreamingContext) Implements ISerializable.GetObjectData
        MyBase.GetObjectData(info, context)
        info.AddValue("ID", _Id)
        info.AddValue("Color", _Color, GetType(GLSerialColor))
        info.AddValue("Border", _Border, GetType(GLSerialPen))
        info.AddValue("TTText", _TTMarker.ToolTipText)
        info.AddValue("TTMode", CType(_TTMarker.ToolTipMode, Byte))
    End Sub
    Public Sub New(info As SerializationInfo, context As StreamingContext)
        MyBase.New(info, context)
        _Type = GLCustomMarkerType.Polygon
        _Id = info.GetString("ID")
        Me.Color = CType(info.GetValue("Color", GetType(GLSerialColor)), GLSerialColor)
        Me.Border = CType(info.GetValue("Border", GetType(GLSerialPen)), GLSerialPen)
        Dim points As GMap.NET.PointLatLng() = CType(info.GetValue("Points", GetType(GMap.NET.PointLatLng())), GMap.NET.PointLatLng())
        _TTMarker = New GMap.NET.WindowsForms.Markers.GMarkerGoogle(points(0), GMap.NET.WindowsForms.Markers.GMarkerGoogleType.blue_small)
        _TTMarker.ToolTipText = info.GetString("TTText")
        _TTMarker.ToolTipMode = CType(info.GetByte("TTMode"), GMap.NET.WindowsForms.MarkerTooltipMode)
    End Sub


End Class

can any one help me please