Setting to toggle fullscreen

On the title screen there should be a new button leading to a Settings-menu. On the preferences screen there should also be a new button leading to the same Settings-menu.

In the Settings Menü there should be a radio-button with two options to enable or disable full-screen. One option is called "windowed" the other option is called "fullscreen". If the Selection is toggled (changed) the change should immediately take effect. After changing the fullscreen a message box should appear that asks if the changes should be kept that way. The Options of the message box should be "yes" and "no". If "yes" is clicked the message box simply colses. If "no" is clicked the last state of the checkbox the effect is reset. In the message box a timer is displayed. The Timer counts down from 10 seconds to 0. If the Timer is expired the message box closes as if "no" was clicked.