public void Update(GameTime gameTime, Scene scene)
        {
            KeyboardState keybState = Keyboard.GetState();

            if (Game.IsActive)
            {
                if (keybState.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.LeftControl) && keybState.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.S))
                {
                    SaveFileDialog saveFileDialog1 = new SaveFileDialog();
                    saveFileDialog1.Filter = "XML file|*.xml";
                    saveFileDialog1.Title = "Save an XML File";
                    DialogResult dr = saveFileDialog1.ShowDialog();
                    if (dr == DialogResult.OK)
                        System.IO.File.WriteAllText(saveFileDialog1.FileName, SceneToXml(scene));
                }
                else if (keybState.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.LeftControl) && keybState.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.O))
                {
                    OpenFileDialog openFileDialog1 = new OpenFileDialog();
                    openFileDialog1.Filter = "XML file|*.xml";
                    openFileDialog1.Title = "Open an XML File";
                    DialogResult dr = openFileDialog1.ShowDialog();
                    if (dr == DialogResult.OK)
                    {
                        scene.Clean();
                        SceneFromXml(openFileDialog1.FileName, scene);
                        Vector2 characterPosition = Vector2.Zero;
                        foreach (Element i in scene.Elements)
                            if (i is Character)
                                characterPosition = i.Position;
                        scene.Camera.Position = characterPosition;
                    }
                }
                else if (keybState.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.LeftControl) && keybState.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.N))
                {
                    if (MessageBox.Show("Are you sure you want to clean the scene?", "New scene", MessageBoxButtons.YesNo) == DialogResult.Yes)
                    {
                        scene.Clean();
                    }
                }
            }
        }