diff --git a/dotnet/AipsRT/Model/Whiteboard/Shapes/Arrow.cs b/dotnet/AipsRT/Model/Whiteboard/Shapes/Arrow.cs
index 6d1a3e3..6e0f51e 100644
--- a/dotnet/AipsRT/Model/Whiteboard/Shapes/Arrow.cs
+++ b/dotnet/AipsRT/Model/Whiteboard/Shapes/Arrow.cs
@@ -10,7 +10,7 @@ public class Arrow : Shape
     
     public override void Move(Position newPosition)
     {
-        var difference = newPosition - EndPosition;
+        var difference = newPosition - Position;
         EndPosition += difference;
         base.Move(newPosition);
     }
diff --git a/dotnet/AipsRT/Model/Whiteboard/Shapes/Line.cs b/dotnet/AipsRT/Model/Whiteboard/Shapes/Line.cs
index 8274a8c..600f45b 100644
--- a/dotnet/AipsRT/Model/Whiteboard/Shapes/Line.cs
+++ b/dotnet/AipsRT/Model/Whiteboard/Shapes/Line.cs
@@ -10,7 +10,7 @@ public class Line : Shape
     
     public override void Move(Position newPosition)
     {
-        var difference = newPosition - EndPosition;
+        var difference = newPosition - Position;
         EndPosition += difference;
         base.Move(newPosition);
     }