If VisualEditor is used to introduce a link (Ctrl-K) and the list of suggested link targets is long enough to require a scroll bar, this scroll bar cannot be used: clicking on it immediately closes the target list.
Version: unspecified
Severity: normal
OS: Windows 7
(Notice that using the mouse wheel works as intended, at least in the categories' case, so assuming it's the same bug we'll need to edit its title.)
Just noticed that the (non-functional) scroll bar is only shown if the target list is displayed too far down on the screen. Otherwise, the list just contains 10 items and no scroll bar. To test on mediawiki.org: start a new empty link with Ctrl-K and type R.