diff --git a/Directory.Build.props b/Directory.Build.props
index ad267061..13ae5d3e 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -3,7 +3,7 @@
         <Product>XAML Map Control</Product>
         <Authors>Clemens Fischer</Authors>
         <Copyright>Copyright © 2026 Clemens Fischer</Copyright>
-        <Version>16.1.0</Version>
+        <Version>16.2.0</Version>
         <AssemblyVersion>$(Version)</AssemblyVersion>
         <AssemblyOriginatorKeyFile>..\..\MapControl.snk</AssemblyOriginatorKeyFile>
         <SignAssembly>true</SignAssembly>
diff --git a/MapsforgeTiles/README.md b/MapsforgeTiles/README.md
index 21427687..127ce2db 100644
--- a/MapsforgeTiles/README.md
+++ b/MapsforgeTiles/README.md
@@ -12,19 +12,18 @@ Map files can be downloaded from the [Mapsforge Download Server](https://downloa
 `MapsforgeTileSource` is initialized by a static `LoadMaps` method that takes the file path to either a single map file
 or a directory containing multiple map files.
 
-The `MapsforgeTileSource` instance constructor takes a string parameter that specifies a Mapsforge theme. This is either
-the full path of an XML `rendertheme` file, or the name of one of the built-in themes (ignoring case), e.g. `Default`.
+The class has a `Theme` property that specifies a Mapsforge theme. This is either the path of an XML `rendertheme` file,
+the path of a ZIP file containing a render theme, or the name of one of the built-in themes (ignoring case), e.g. `Default`.
 See [MapsforgeThemes.java](https://github.com/mapsforge/mapsforge/blob/master/mapsforge-themes/src/main/java/org/mapsforge/map/rendertheme/internal/MapsforgeThemes.java)
-for available theme names. An additional constructor parameters specifies the size of the tile source's internal cache.
+for available theme names.
 
 Code sample:
 ```
 MapControl.MapsforgeTiles.MapsforgeTileSource.LoadMaps(".\mapfiles");
 
-map.MapLayer = new MapTileLayer
-{
-    TileSource = new MapControl.MapsforgeTiles.MapsforgeTileSource("Default")
-};
+var tileSource = new MapControl.MapsforgeTiles.MapsforgeTileSource { Theme = "Default" };
+
+map.MapLayer = new MapTileLayer { TileSource = tileSource };
 ```
 
 ---
diff --git a/MapsforgeTiles/Shared/MapsforgeTileSource.cs b/MapsforgeTiles/Shared/MapsforgeTileSource.cs
index ace12580..3d043fdd 100644
--- a/MapsforgeTiles/Shared/MapsforgeTileSource.cs
+++ b/MapsforgeTiles/Shared/MapsforgeTileSource.cs
@@ -83,45 +83,7 @@ namespace MapControl.MapsforgeTiles
         {
             if (renderThemeFuture == null)
             {
-                lock (displayModel)
-                {
-                    if (renderThemeFuture == null)
-                    {
-                        if (mapDataStore == null)
-                        {
-                            throw new InvalidOperationException("No map files loaded.");
-                        }
-
-                        Logger?.LogInformation("Loading render theme \"{theme}\".", Theme);
-
-                        ZipInputStream zipInputStream = null;
-                        XmlRenderTheme renderTheme;
-
-                        if (Theme.EndsWith(".zip"))
-                        {
-                            zipInputStream = new ZipInputStream(new FileInputStream(Theme));
-                            renderTheme = new ZipRenderTheme(
-                                Path.GetFileName(Theme).Replace(".zip", ".xml"),
-                                new ZipXmlThemeResourceProvider(zipInputStream));
-                        }
-                        else if (Theme.EndsWith(".xml"))
-                        {
-                            renderTheme = new ExternalRenderTheme(Theme);
-                        }
-                        else
-                        {
-                            renderTheme = MapsforgeThemes.valueOf(Theme.ToUpper());
-                        }
-
-                        tileCache = new InMemoryTileCache(CacheCapacity);
-                        renderer = new DatabaseRenderer(mapDataStore, AwtGraphicFactory.INSTANCE, tileCache, null, true, false, null);
-                        renderThemeFuture = new RenderThemeFuture(AwtGraphicFactory.INSTANCE, renderTheme, displayModel);
-                        renderThemeFuture.run();
-                        zipInputStream?.close();
-
-                        Logger?.LogInformation("Loading render theme done.");
-                    }
-                }
+                Initialize();
             }
 
             int[] imageBuffer = null;
@@ -141,5 +103,48 @@ namespace MapControl.MapsforgeTiles
 
             return imageBuffer;
         }
+
+        private void Initialize()
+        {
+            lock (displayModel)
+            {
+                if (renderThemeFuture == null)
+                {
+                    if (mapDataStore == null)
+                    {
+                        throw new InvalidOperationException("No map files loaded.");
+                    }
+
+                    Logger?.LogInformation("Loading render theme \"{theme}\".", Theme);
+
+                    ZipInputStream zipInputStream = null;
+                    XmlRenderTheme renderTheme;
+
+                    if (Theme.EndsWith(".zip"))
+                    {
+                        zipInputStream = new ZipInputStream(new FileInputStream(Theme));
+                        renderTheme = new ZipRenderTheme(
+                            Path.GetFileName(Theme).Replace(".zip", ".xml"),
+                            new ZipXmlThemeResourceProvider(zipInputStream));
+                    }
+                    else if (Theme.EndsWith(".xml"))
+                    {
+                        renderTheme = new ExternalRenderTheme(Theme);
+                    }
+                    else
+                    {
+                        renderTheme = MapsforgeThemes.valueOf(Theme.ToUpper());
+                    }
+
+                    tileCache = new InMemoryTileCache(CacheCapacity);
+                    renderer = new DatabaseRenderer(mapDataStore, AwtGraphicFactory.INSTANCE, tileCache, null, true, false, null);
+                    renderThemeFuture = new RenderThemeFuture(AwtGraphicFactory.INSTANCE, renderTheme, displayModel);
+                    renderThemeFuture.run();
+                    zipInputStream?.close();
+
+                    Logger?.LogInformation("Loading render theme done.");
+                }
+            }
+        }
     }
 }