diff --git a/src/main/java/com/mapconductor/maptiler/MapTilerMapView.kt b/src/main/java/com/mapconductor/maptiler/MapTilerMapView.kt
index 7c54322..556e8fa 100644
--- a/src/main/java/com/mapconductor/maptiler/MapTilerMapView.kt
+++ b/src/main/java/com/mapconductor/maptiler/MapTilerMapView.kt
@@ -239,6 +239,20 @@ fun MapTilerMapSurface(
             onDispose { state.serviceRegistry.remove(MarkerRenderingSupportKey) }
         }
 
+        // MTMapView destroys its WebView itself; the controller (tile-server
+        // routes, overlay managers, its coroutine scope) is ours to free. Keyed
+        // like the WebView, so a design change frees the one it replaces.
+        DisposableEffect(controller) {
+            onDispose {
+                controller.destroy()
+                // No MapViewBase here to do it: the state (which the app keeps) must
+                // not hold on to the destroyed controller and its overlays. Only if
+                // it is still the attached one -- after a design change the new
+                // controller is attached before this runs.
+                state.detachController(controller)
+            }
+        }
+
         // 設定を渡すだけ。**タイル経路に倒すかはコントローラが件数を見て決める**
         // （`shouldUseMarkerLayer`）。ここで `useMarkerLayer = markerTiling != null` と
         // 書くと、しきい値未満の件数でもタイル経路に落ちてマーカーが 1 つも描かれない。
diff --git a/src/main/java/com/mapconductor/maptiler/MapTilerViewStateImpl.kt b/src/main/java/com/mapconductor/maptiler/MapTilerViewStateImpl.kt
index 3d3b926..07f00a2 100644
--- a/src/main/java/com/mapconductor/maptiler/MapTilerViewStateImpl.kt
+++ b/src/main/java/com/mapconductor/maptiler/MapTilerViewStateImpl.kt
@@ -38,7 +38,10 @@ class MapTilerViewState(
     MapTilerViewStateInterface {
     private var _mapDesignType by mutableStateOf(mapDesignType)
 
-    private var controller: MapTilerMapViewController? = null
+    // Read through the base so that letting go of the controller there (MapViewBase
+    // does it when the map is torn down) leaves nothing behind here.
+    private val controller: MapTilerMapViewController?
+        get() = attachedMapController as? MapTilerMapViewController
 
     override var mapDesignType: MapTilerMapDesignTypeInterface
         get() = _mapDesignType
@@ -49,7 +52,6 @@ class MapTilerViewState(
 
     /** MapView 生成時にコントローラを紐付ける。 */
     fun setController(controller: MapTilerMapViewController) {
-        this.controller = controller
         // 初期カメラは MTMapOptions で地図生成時に渡しているので、接続時には移動しない。
         attachController(controller, moveToInitialCamera = false)
     }