Set the canvas size to 0 on dispose

src/ol/render/canvas/ExecutorGroup.js

@@ -143,6 +143,8 @@ class ExecutorGroup extends Disposable {
         executors[key].disposeInternal();
       }
     }
+    const canvas = this.hitDetectionContext_.canvas;
+    canvas.width = canvas.height = 0;
     super.disposeInternal();
   }
 

src/ol/renderer/canvas/Layer.js

@@ -63,6 +63,14 @@ class CanvasLayerRenderer extends LayerRenderer {
     canvas.className = this.getLayer().getClassName();
   }
 
+  /**
+   * @inheritDoc
+   */
+  disposeInternal() {
+    this.context.canvas.width = this.context.canvas.height = 0;
+    super.disposeInternal();
+  }
+
   /**
    * @param {CanvasRenderingContext2D} context Context.
    * @param {import("../../PluggableMap.js").FrameState} frameState Frame state.

src/ol/renderer/canvas/VectorTileLayer.js

@@ -152,6 +152,7 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
    */
   disposeInternal() {
     unlisten(labelCache, EventType.CLEAR, this.handleFontsChanged_, this);
+    this.overlayContext_.canvas.width = this.overlayContext_.canvas.height = 0;
     super.disposeInternal();
   }