Hello,
It works by pressing middle mouse button and dragging mouse up/down.
Note that it won't work HERE, on this addons store page (as a security measure, all addons are blocked here).
It's best to test the scrolling in the Options page.
Best Regards,
Juraj Mäsiar

Hello Ran,
There have not been any update mostly because everything works same as before, and there were not a lot of new feature requests.

Note that "remembering scroll position" is not something that would my addon do. It only scrolls the page as a direct result of user action (mouse move while scrolling button is down). I think browser should remember scroll position automatically.
Also "zoomed picture" is very unlikely related to this addon.
And over-scrolling is again, something a page should handle (some pages are badly designed with overflowing elements outside the boundaries).

Maybe you have also some other scroll related addons that breaks these?

Best Regards,
Juraj Mäsiar