Adjustments

src/core/viewport.ts

      */
     release(): void
     {
-        this._container.style.backgroundColor = 'initial';
-        this._container.style.touchAction = 'auto';
+        this._container.style.removeProperty('background-color');
+        this._container.style.removeProperty('touch-action');
     }
 }
 
 
         parent.appendChild(this._backgroundCanvas);
         parent.appendChild(this._foregroundCanvas);
+
+        this._backgroundCanvas.hidden = true;
+        this._foregroundCanvas.hidden = true;
     }
 
     /**
      */
     init(): void
     {
+        this._backgroundCanvas.hidden = false;
+        this._foregroundCanvas.hidden = false;
     }
 
     /**
     private readonly _containers: ViewportContainers;
 
     /** An overlay displayed in front of the augmented scene */
-    protected readonly _hud: HUD;
+    private readonly _hud: HUD;
 
     /** Viewport style */
-    protected _style: ViewportStyle;
+    private _style: ViewportStyle;
 
     /** The canvases of the viewport */
     private readonly _canvases: ViewportCanvases;