Won;t stop scrolling

Using win10 fully updated, pro on one computer, home on the other.

Often, when I click on the vertical scroll bar, not at the ends, but in the middle, instead of scrolling one page, it just keeps scrolling, even though I used a very quick touch. It can go 10 pages before it stops.

I thought it was the mouse so I changed mice, but it's the same, and it's the same on the other computer.

???

Using the common Dell mouse in all 3 cases.

Thanks Spunk. That will help, esp. if I can't fix the original problem. I think maybe I bought a bunch of bad mice and I'll look around here for another one or buy one. I think I got them all at hamfests and ebay, and maybe the left key "chatters". Not that all Dell mice are like this but the ones that were like this got send to the after-market market.