Discovered when testing https://gerrit.wikimedia.org/r/#/c/227181/ : Start adding a links, get the suggested links list (now scrollable), then use the two-finger scroll to scroll the page up and down (using the mouse wheel probably has the same effect, but I don't have a wheel mouse to try it).
Observed: The whole list detaches itself from the link tool and moves up and down with the page.
Expected: The list is supposed to stay attached to the link tool in any case. When using the two-finger scroll inside the list, the links list should scroll. When using it outside the tool, the page should scroll and the links list must stay at one place.
This is a follow-up to T106528.