diff --git a/MapControl/Shared/MapImageLayer.cs b/MapControl/Shared/MapImageLayer.cs
index 8b5ab5c1..824fbe78 100644
--- a/MapControl/Shared/MapImageLayer.cs
+++ b/MapControl/Shared/MapImageLayer.cs
@@ -204,15 +204,12 @@ namespace MapControl
 
                 base.OnViewportChanged(e);
 
-                if (updateTimer.IsEnabled && !UpdateWhileViewportChanging)
+                if (!UpdateWhileViewportChanging)
                 {
                     updateTimer.Stop(); // restart
                 }
 
-                if (!updateTimer.IsEnabled)
-                {
-                    updateTimer.Start();
-                }
+                updateTimer.Start();
             }
         }
 
diff --git a/MapControl/Shared/MapTileLayer.cs b/MapControl/Shared/MapTileLayer.cs
index 1f97e7e5..2a55526d 100644
--- a/MapControl/Shared/MapTileLayer.cs
+++ b/MapControl/Shared/MapTileLayer.cs
@@ -82,29 +82,30 @@ namespace MapControl
 
         protected override void UpdateTileLayer(bool tileSourceChanged)
         {
-            var update = false;
+            var updateTiles = false;
 
             if (ParentMap == null || !ParentMap.MapProjection.IsWebMercator)
             {
+                Tiles.Clear();
                 TileMatrix = null;
-                update = true;
+                updateTiles = true;
             }
             else
             {
                 if (tileSourceChanged)
                 {
                     Tiles.Clear();
-                    update = true;
+                    updateTiles = true;
                 }
 
                 if (SetTileMatrix())
                 {
                     SetRenderTransform();
-                    update = true;
+                    updateTiles = true;
                 }
             }
 
-            if (update)
+            if (updateTiles)
             {
                 UpdateTiles();
             }
@@ -154,10 +155,9 @@ namespace MapControl
 
         private void UpdateTiles()
         {
-            var newTiles = new List<Tile>();
-
             if (ParentMap != null && TileMatrix != null && TileSource != null)
             {
+                var newTiles = new List<Tile>();
                 var maxZoomLevel = Math.Min(TileMatrix.ZoomLevel, MaxZoomLevel);
 
                 if (maxZoomLevel >= MinZoomLevel)
@@ -201,9 +201,9 @@ namespace MapControl
                         }
                     }
                 }
-            }
 
-            Tiles = newTiles;
+                Tiles = newTiles;
+            }
 
             Children.Clear();
 
diff --git a/MapControl/Shared/MapTileLayerBase.cs b/MapControl/Shared/MapTileLayerBase.cs
index dd5766ca..ec0d4f13 100644
--- a/MapControl/Shared/MapTileLayerBase.cs
+++ b/MapControl/Shared/MapTileLayerBase.cs
@@ -170,15 +170,12 @@ namespace MapControl
             {
                 SetRenderTransform();
 
-                if (updateTimer.IsEnabled && !UpdateWhileViewportChanging)
+                if (!UpdateWhileViewportChanging)
                 {
                     updateTimer.Stop(); // restart
                 }
 
-                if (!updateTimer.IsEnabled)
-                {
-                    updateTimer.Start();
-                }
+                updateTimer.Start();
             }
         }