// containsMouse changes, but the color never be updated if
                    // the renderPolicy is OnDemand.
                    DiffuseSpecularMaterial {
                        id: material
                        ambient: picker.containsMouse ? "red" : "blue"
                    },
                    ObjectPicker {
                        id: picker
                        hoverEnabled: true
                        onContainsMouseChanged: {
                            console.log("containsMouse:", containsMouse);
                            // If the change is not triggered within the current
                            // event loop, it works. Uncomment this to test the
                            // behavior.
                            Qt.callLater(() => {
                                //material.ambient = containsMouse ? "red" : "blue";
                            });
                        }
                    }