Most of the time, the script works just fine. However, if you suspend the laptop for the night and come back in the morning, in all likelihood, your timeline will be populated in chunks. The GUI loads a chunk, and puts the button with the ellipsis, then you click on it to load another chunk until everything is loaded.
The script does detect the click on the ellipsis, but it scrolls the column incorrectly.
This is hard to test right now. I don't really know how to create the conditions for the ellipsis button to appear.