Bookmark buttons depends only of the current loaded page
When a button is pressed, on any bookmark, the action depends from the current page loaded and not the bookmark.
But my question, is, then, why are these buttons attached to the bookmarks instead of the shuttle icon ? It is already very hard to "catch" the buttons when they move up and down.
This is part of the design, we did not know where to place the buttons without taking up too much space.
I agree with the fact that you wanted to save space. The aspect that I don't understand as a user is : why these buttons placed next to hovered bookmark. They could appear when you are hovering the shuttle logo.
It's a good idea, I'll talk with the designer to see if we can integrate it.