Test for https://github.com/BabylonJS/Babylon.js/pull/8163, to be placed in localDev/src/

index.1.js

var createScene = function () {
    // Create basic scene
    var scene = new BABYLON.Scene(engine);
    var camera = new BABYLON.FreeCamera("camera1", new BABYLON.Vector3(0, 5, -10), scene);
    camera.setTarget(BABYLON.Vector3.Zero());
    camera.attachControl(canvas, true);
    var light = new BABYLON.HemisphericLight("light1", new BABYLON.Vector3(0, 1, 0), scene);
    light.intensity = 0.7;
    var sphere = BABYLON.Mesh.CreateSphere("sphere1", 16, 2, scene);
    sphere.rotation.z = Math.PI/2
    sphere.position.y = 1;
    var ground = BABYLON.Mesh.CreateGround("ground1", 6, 6, 2, scene);

    // Create utility layer the gizmo will be rendered on
    var utilLayer = new BABYLON.UtilityLayerRenderer(scene);

    var gizmoManager = new BABYLON.GizmoManager(scene)
    gizmoManager.boundingBoxGizmoEnabled = true
    gizmoManager.positionGizmoEnabled = true
    gizmoManager.rotationGizmoEnabled = true
    gizmoManager.gizmos.positionGizmo.yPlaneGizmo.isEnabled = true

    gizmoManager.attachedMesh = sphere;

    // Keep the gizmo fixed to world rotation
    gizmoManager.updateGizmoRotationToMatchAttachedMesh = false;
    
    // Toggle gizmo on keypress
    document.onkeydown = ()=>{
        gizmo.attachedMesh = !gizmo.attachedMesh ? sphere : null
    }
    return scene;

};