On Windows, if you’re click-drag scrolling using a standard scrollbar (say, in file explorer), and you move the mouse about 50 pixels away horizontally from the scrollbar without letting up on the mouse button, the scroll position snaps back to its original location before scrolling began. If you move your mouse back into the 50 pixel range again, the scrollbar then snaps back to the new scroll position.
This allows you to “preview” scrolling to a new location, and then if you don’t want to actually scroll then, you can simply move your mouse out of the 50 pixel region and effectively cancel your scroll.
It would be great if Sublime supported this behavior (it’s a standard Windows thing, and I’m realizing I miss it in Sublime quite a bit when browsing source files).