I just updated Pr to the lastest version. Before the update when I scroll the middle mouse wheel while having the mouse over the program monitor (the main window where it plays the video), the action was going forward or backward in the timeline like when pressing back or forward key on the keyboard. But now it's zooming the video, which I personally barely use. I thought having it able to scrub throught timeline is much much more useful than zooming, and I hope in the future updates it can be at least added back as an option so we can choose what action the middle mouse does deoends on personal preferences, as oppsed to completely reaplacing and removing it.