Handles the exit of the selection screen. Sets the new background, if necessary, and
calls the previously defined callback function. Then exits the screen to the screen, the player was before
Parameters
SetBackground: boolean
Defines, wether the background must be changed (true) or not (false)
Handles the exit of the selection screen. Sets the new background, if necessary, and calls the previously defined callback function. Then exits the screen to the screen, the player was before