better json serializable PaintingObjects

Pilz.UI/PaintingControl/PaintingObjectLayering.vb

@@ -1,11 +1,22 @@
-Public Class PaintingObjectLayering
+Imports Newtonsoft.Json
 
+Public Class PaintingObjectLayering
+
+    <JsonProperty(NameOf(PaintingObject))>
+    Private ReadOnly _PaintingObject As PaintingObject
+
+    <JsonIgnore>
     Public ReadOnly Property PaintingObject As PaintingObject
+        Get
+            Return _PaintingObject
+        End Get
+    End Property
 
     ''' <summary>
     ''' Get the current object list from the painting object.
     ''' </summary>
     ''' <returns>Returns the current object list from the painting object.</returns>
+    <JsonIgnore>
     Public ReadOnly Property ObjectList As PaintingObjectList
         Get
             Return PaintingObject.Parent.PaintingObjects
@@ -17,7 +28,7 @@
     ''' </summary>
     ''' <param name="obj"></param>
     Public Sub New(obj As PaintingObject)
-        PaintingObject = obj
+        _PaintingObject = obj
     End Sub
 
     ''' <summary>