There's currently a bug that makes the "Prevent rapid triggering" checkbox look like it's off even if it's actually on.
Workaround: Click it once and it will display the current status.
Please report bugs to firstname.lastname@example.org
Infrared ball trigger sensors not working correctly? Try placing them higher up. This usually increases their reliability since less of the light will be reflected on the lane surface. If using the set bought from 86Pixels, contact him directly.