Can not use mouse to change viewport in scene3D.

[small_bird]

Hello everyone, I have the following code:

import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Controls 1.4
import QtQuick.Controls.Styles 1.4
import Qt3D.Core 2.0
import Qt3D.Render 2.0
import Qt3D.Input 2.0
import Qt3D.Extras 2.0
import QtQuick.Scene3D 2.0

ApplicationWindow{
    width: Screen.desktopAvailableWidth;
    height: Screen.desktopAvailableHeight;
    Scene3D{
        id:scene3d;
        anchors.fill: parent;

        Entity {
            id: sceneRoot;

            Camera {
                id: camera;
                projectionType: CameraLens.PerspectiveProjection;
                fieldOfView: 45;
                aspectRatio: Screen.desktopAvailableWidth / Screen.desktopAvailableHeight;
                nearPlane: 0.1;
                farPlane: 1000.0;
                position: Qt.vector3d(0.0, 10.0, 20.0);
                viewCenter: Qt.vector3d(0.0, 0.0, 0.0);
                upVector: Qt.vector3d(0.0, 1.0, 0.0);
            }

            FirstPersonCameraController {
                camera: camera;
            }

            ShadowMapLight {
                id: light;
            }
            components: [
                ShadowMapFrameGraph {
                    id: framegraph;
                    viewCamera: camera;
                    lightCamera: light.lightCamera;
                },
                // Event Source will be set by the Qt3DQuickWindow
                InputSettings { }
            ]

            AdsEffect {
                id: shadowMapEffect;
                shadowTexture: framegraph.shadowTexture;
                light: light;
            }

            // Trefoil knot entity
            Trefoil {
                material: AdsMaterial {
                    effect: shadowMapEffect;
                    specularColor: Qt.rgba(0.5, 0.5, 0.5, 1.0);
                }
            }

            // Toyplane entity
            Toyplane {
                material: AdsMaterial {
                    effect: shadowMapEffect;
                    diffuseColor: Qt.rgba(0.9, 0.5, 0.3, 1.0);
                    shininess: 75;
                }
            }

            // Plane entity
            GroundPlane {
                material: AdsMaterial {
                    effect: shadowMapEffect;
                    diffuseColor: Qt.rgba(0.2, 0.5, 0.3, 1.0);
                    specularColor: Qt.rgba(0, 0, 0, 1.0);
                }
            }
        }
    }
}

However, I can not use the mouse to change viewport in scene3D, could anyone tell me the reason? Thanks in advance!