diff --git a/MapControl/Shared/MapProjection.cs b/MapControl/Shared/MapProjection.cs
index 33377985..aa0a59d6 100644
--- a/MapControl/Shared/MapProjection.cs
+++ b/MapControl/Shared/MapProjection.cs
@@ -198,7 +198,7 @@ namespace MapControl
             InverseViewportTransform = matrix;
         }
 
-        internal Matrix CreateViewportTransform(Point mapCenter, Point viewportCenter)
+        private Matrix CreateViewportTransform(Point mapCenter, Point viewportCenter)
         {
             var matrix = new Matrix(ViewportScale, 0d, 0d, -ViewportScale, -ViewportScale * mapCenter.X, ViewportScale * mapCenter.Y);
 
@@ -215,13 +215,13 @@ namespace MapControl
 
             matrix.Rotate(ViewportRotation);
 
-            // tile grid origin in map cordinates
+            // tile grid origin in map coordinates
             //
             var mapOrigin = new Point(
                 tileGridTopLeft.X + tileGridOrigin.X / tileGridScale,
                 tileGridTopLeft.Y - tileGridOrigin.Y / tileGridScale);
 
-            // tile grid origin in viewport cordinates
+            // tile grid origin in viewport coordinates
             //
             var viewOrigin = ViewportTransform.Transform(mapOrigin);
 
diff --git a/MapControl/Shared/MapTileLayer.cs b/MapControl/Shared/MapTileLayer.cs
index 54609bec..9c7383a7 100644
--- a/MapControl/Shared/MapTileLayer.cs
+++ b/MapControl/Shared/MapTileLayer.cs
@@ -63,10 +63,10 @@ namespace MapControl
         {
         }
 
-        public IReadOnlyCollection<Tile> Tiles { get; private set; } = new List<Tile>();
-
         public TileGrid TileGrid { get; private set; }
 
+        public IReadOnlyCollection<Tile> Tiles { get; private set; } = new List<Tile>();
+
         /// <summary>
         /// Minimum zoom level supported by the MapTileLayer. Default value is 0.
         /// </summary>
@@ -85,37 +85,6 @@ namespace MapControl
             set { SetValue(MaxZoomLevelProperty, value); }
         }
 
-        protected override Size MeasureOverride(Size availableSize)
-        {
-            availableSize = new Size(double.PositiveInfinity, double.PositiveInfinity);
-
-            foreach (var tile in Tiles)
-            {
-                tile.Image.Measure(availableSize);
-            }
-
-            return new Size();
-        }
-
-        protected override Size ArrangeOverride(Size finalSize)
-        {
-            if (TileGrid != null)
-            {
-                foreach (var tile in Tiles)
-                {
-                    var tileSize = TileSize << (TileGrid.ZoomLevel - tile.ZoomLevel);
-                    var x = tileSize * tile.X - TileSize * TileGrid.XMin;
-                    var y = tileSize * tile.Y - TileSize * TileGrid.YMin;
-
-                    tile.Image.Width = tileSize;
-                    tile.Image.Height = tileSize;
-                    tile.Image.Arrange(new Rect(x, y, tileSize, tileSize));
-                }
-            }
-
-            return finalSize;
-        }
-
         protected override void TileSourcePropertyChanged()
         {
             if (TileGrid != null)
@@ -242,5 +211,36 @@ namespace MapControl
 
             TileImageLoader.LoadTilesAsync(Tiles, TileSource, SourceName);
         }
+
+        protected override Size MeasureOverride(Size availableSize)
+        {
+            availableSize = new Size(double.PositiveInfinity, double.PositiveInfinity);
+
+            foreach (var tile in Tiles)
+            {
+                tile.Image.Measure(availableSize);
+            }
+
+            return new Size();
+        }
+
+        protected override Size ArrangeOverride(Size finalSize)
+        {
+            if (TileGrid != null)
+            {
+                foreach (var tile in Tiles)
+                {
+                    var tileSize = TileSize << (TileGrid.ZoomLevel - tile.ZoomLevel);
+                    var x = tileSize * tile.X - TileSize * TileGrid.XMin;
+                    var y = tileSize * tile.Y - TileSize * TileGrid.YMin;
+
+                    tile.Image.Width = tileSize;
+                    tile.Image.Height = tileSize;
+                    tile.Image.Arrange(new Rect(x, y, tileSize, tileSize));
+                }
+            }
+
+            return finalSize;
+        }
     }
 }
diff --git a/MapControl/Shared/WmtsTileLayer.cs b/MapControl/Shared/WmtsTileLayer.cs
index 5fb98eaa..8571ecad 100644
--- a/MapControl/Shared/WmtsTileLayer.cs
+++ b/MapControl/Shared/WmtsTileLayer.cs
@@ -33,6 +33,8 @@ namespace MapControl
         public WmtsTileLayer(ITileImageLoader tileImageLoader)
             : base(tileImageLoader)
         {
+            IsHitTestVisible = false;
+
             Loaded += OnLoaded;
         }
 
@@ -48,11 +50,16 @@ namespace MapControl
             set { SetValue(LayerIdentifierProperty, value); }
         }
 
+        public IEnumerable<WmtsTileMatrixLayer> ChildLayers
+        {
+            get { return Children.Cast<WmtsTileMatrixLayer>(); }
+        }
+
         public Dictionary<string, WmtsTileMatrixSet> TileMatrixSets { get; } = new Dictionary<string, WmtsTileMatrixSet>();
 
         protected override Size MeasureOverride(Size availableSize)
         {
-            foreach (var layer in Children.Cast<WmtsTileMatrixLayer>())
+            foreach (var layer in ChildLayers)
             {
                 layer.Measure(availableSize);
             }
@@ -62,7 +69,7 @@ namespace MapControl
 
         protected override Size ArrangeOverride(Size finalSize)
         {
-            foreach (var layer in Children.Cast<WmtsTileMatrixLayer>())
+            foreach (var layer in ChildLayers)
             {
                 layer.Arrange(new Rect(0, 0, finalSize.Width, finalSize.Height));
             }
@@ -95,7 +102,7 @@ namespace MapControl
 
         protected override void SetRenderTransform()
         {
-            foreach (var layer in Children.Cast<WmtsTileMatrixLayer>())
+            foreach (var layer in ChildLayers)
             {
                 layer.SetRenderTransform(ParentMap.MapProjection);
             }
@@ -106,7 +113,7 @@ namespace MapControl
             var layersChanged = false;
             var maxScale = 1.001 * ParentMap.MapProjection.ViewportScale; // avoid rounding issues
 
-            // show all TileMatrix layers with Scale <= maxScale, or at least the first layer
+            // show all TileMatrix layers with Scale <= maxScale, at least the first layer
             //
             var currentMatrixes = tileMatrixSet.TileMatrixes
                 .Where((matrix, i) => i == 0 || matrix.Scale <= maxScale)
@@ -121,9 +128,7 @@ namespace MapControl
                 currentMatrixes = currentMatrixes.Skip(currentMatrixes.Count - MaxBackgroundLevels - 1).ToList();
             }
 
-            var currentLayers = Children.Cast<WmtsTileMatrixLayer>()
-                .Where(layer => currentMatrixes.Contains(layer.TileMatrix))
-                .ToList();
+            var currentLayers = ChildLayers.Where(layer => currentMatrixes.Contains(layer.TileMatrix)).ToList();
 
             Children.Clear();
 
@@ -152,7 +157,7 @@ namespace MapControl
         {
             var tiles = new List<Tile>();
 
-            foreach (var layer in Children.Cast<WmtsTileMatrixLayer>())
+            foreach (var layer in ChildLayers)
             {
                 layer.UpdateTiles();
 
diff --git a/MapControl/Shared/WmtsTileMatrixLayer.cs b/MapControl/Shared/WmtsTileMatrixLayer.cs
index 2700ad37..c12422c3 100644
--- a/MapControl/Shared/WmtsTileMatrixLayer.cs
+++ b/MapControl/Shared/WmtsTileMatrixLayer.cs
@@ -28,7 +28,8 @@ namespace MapControl
         }
 
         public WmtsTileMatrix TileMatrix { get; }
-        public int ZoomLevel { get; }
+        public int ZoomLevel { get; } // index of TileMatrix in WmtsTileMatrixSet.TileMatrixes
+
         public int XMin { get; private set; }
         public int YMin { get; private set; }
         public int XMax { get; private set; }