I have had this problem on multiple computers I think going back to even Windows XP, 7 and now 8.2 (or whatever it's up to now).
Say I want to upload a photo to a website. I click on "upload" and my picture folder opens.
I start scrolling down through the hundreds of photos using the side bar which allows "page down/up".
All of a sudden, it will start rapidly paging down, like the left mouse button is stuck, like I am hitting page down on the side bar.
I can click outside the box and stop it, but this is gettting annoying after several months/years of this occuring.
What causes this and how do I fix it?