/// <summary>
        /// Creates an stage, north of the current stage.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ButtonUpStage_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                if (currentID < 0)
                {
                    throw new Exception();
                }

                if ((string)ButtonUpStage.Content == "↑")
                {
                    currentID = manager.GetStage(currentID).ExitUp;

                    CheckExits();

                    LoadStageCanvas();
                }
                else
                {
                    int previousID = manager.ID;

                    StageWindow stageWindow = new StageWindow(manager, false, null);
                    stageWindow.ShowDialog();

                    if (previousID != manager.ID)
                    {
                        Stage previous = manager.GetStage(currentID);

                        previous.ExitUp = manager.ID;

                        Stage current = manager.GetStage(manager.ID);

                        current.ExitDown = currentID;

                        currentID = manager.ID;

                        LoadStageCanvas();

                        CheckExits();
                    }
                }
            }
            catch (Exception)
            {
                MessageBox.Show("You have to create the first stage.", "Attention", MessageBoxButton.OK, MessageBoxImage.Information);
            }
        }
        /// <summary>
        /// Lets you create the first level, and modify any level after the first is created.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ButtonModifyStage_Click(object sender, RoutedEventArgs e)
        {
            if ((string)ButtonModifyStage.Content == "Create")
            {
                StageWindow stageWindow = new StageWindow(manager, false, null);
                stageWindow.ShowDialog();

                if (manager.ID == 0)
                {
                    currentID = 0;
                    ButtonModifyStage.Content = "Modify";

                    LoadStageCanvas();
                }
            }
            else
            {
                StageWindow stageWindow = new StageWindow(manager, true, manager.GetStage(currentID));
                stageWindow.ShowDialog();

                LoadStageCanvas();
            }
        }