Vertical scroll bar keeps jumping to the bottom of the screen

I'm now using a USB mouse. After about 1 hour of use, I have yet to see it exhibit the scrolling defect that was increasingly-frequent in my bluetooth mouse.

I dunno yet whether it's a hardware issue, or a software one (due to the difference between the driver-stack in a USB vs a bluetooth connection to a mouse). I'm thinking it's most-likely a hardware fault; anyway on my round-to-it list is to purchase another bluetooth mouse. I'll post my findings here.

Mice are not 100% reliable!

Your mileage may vary, but my issue is now sorted -- with a new bluetooth mouse!

If you are still having difficulty with the mouse-scrolling misbehaviour, I'd recommend you try a different mouse. You too might find that the old mouse was the root cause of this very annoying & mystifying usability defect.

I have now had 1 week of faultfree operation with this newly-purchased mouse.

My old USB mouse worked fine too, but its dongle was annoying.

I'm posting today because, when I reconnected my old bluetooth mouse, it immediately misbehaved. This makes me very confident that the issue was with the old mouse, and not with any software. (It's hard to diagnose these intermittent defects, especially when software e.g. in the browser can (and is!) updated at any time without any obvious notice.)

Just over a week ago, I had opened up the misbehaving bluetooth mouse (which wasn't easy, it's not designed to be repairable), I had seen some tiny hairs on the spoked wheel which (to the best of my understanding) has a photoelectric sensor to detect whenever the wheel is spinning. I tried to clean it out but it still misbehaved... so I purchased a new mouse.

I hope a new mouse sorts the problem for you too!

Woo hoo!!! I don't know what they did, but I did nothing and it is working again. The ribbon is not disappearing when scrolling through mail. I hope it is well for all who had this issue. Someone figured it out and I commend them.

Same problem here, and I'm also without ads (educational institution email system). I also have the problem when opening an email (sporadic) and when returning to the Inbox from an email (if the ribbon was visible on the page where the email is open).

I have this exact problem and do not see ads.

Well, that's funny you say that. I bought a new mouse, but not for hardware issues but because I dropped and cracked mine. But, if it were the mouse, then everyone who has this issue starting in mid May would have to have replaced their mouse.