You will need to reset the window that gave you the bonus item, and then have the number of windows activated for which bonus prize you would like.
For example, if you have 8 windows activated but would like the 4th Window Bonus Prize again, you will need to reset 5 windows, leaving you with 3 windows lit up. Once you reactivate any window, you will be granted the 4th Window Bonus Prize again! But be very sure you've reset the window that originally gave you the bonus prize. You do not need to reactivate that specific window to get the bonus prize again, though.