I have attached an image which explains which element I am talking about. I am trying to find out it's proper name.
Can anyone help me please?
"Handle". However, it's usually prefixed by its intended use: "drag handle", "resize handle", "scroll handle", etc.
(From left to right: scroll handle, rotate handle, resize handle, sort handle.)
Im don't think there is an official term for these. Use of the word "Drag" definitely makes sense but I dont know if "handle" is the right description either as it is visually nothing like a handle.
I have also used and heard "Grip" or "Grip Bars"... Maybe we can coin a new term, What about "Drag Grip"?
When you say "sliding", do you mean dragging? If so, I would call that a "grab handle".