When Find-A-Record has finished searching through the number of generations you chose, it will show a "Load another generation" button. Clicking that button will resume the search through one more generation. If you started with 4 generations then it will search through the 5th generation after clicking the "Load another generation" button. When the search is finished through that generation it will show the "Load another generation" button again.
This replaces the previous "infinite scrolling" behavior that would only load when you scrolled to the bottom of the list. Now that you tell Find-A-Record how far to search, you can start a search and leave it alone to load automatically. Want to search 15 generations for all ancestors with record hints? Now you can.