In Visual Studio 2015/2017, how can we hide the Vertical Scrollbar's grey dots as shown below?
If you're trying to hide the gray dots caused by "Suggestions" (as opposed to bookmarks) then this is the specific setting for that.
Tools --> Options --> Environment --> Fonts and Colors
Select Suggestion ellipses (...) and set the Item foreground to Automatic
Note that this will cause the suggestion ellipses (3 little dots under timer1 in the image below) in your code to also be invisible.