I have recently tried to use it, but couldn't find a way to open files from local computer in it. It showed me a fake filesystem and dragging and dropping files also didn't work.

I have not used another web browser LO thing, I think. If you are talking about another thing, do you have demo site/link?

> Perhaps you meant: "View -> Toolbars -> Track Changes..."

No, I mean a mode or so that is like online word processors like Google Docs, where you see the cursor of someone else, with their name, and can see them typing live, while you are also typing somewhere in the document. Unless "Track Changes" somehow enables connecting to someone else and seeing their actions concurrently, it is not what I am talking about. I really mean collaboratively editing a document, at the same time, seeing changes others make live, not merging afterwards (the git model).