https://bugs.winehq.org/show_bug.cgi?id=43998
--- Comment #3 from Rafał Mużyło galtgendo@o2.pl --- ...a bit more info from a different app suffering from the same problem:
There, the treeview is contained within a scrolled window (H&V). Anyway, it seems that the difference between the row you think you click in and the row you've actually clicked is a rounding problem. What I've seen is that there the treeview content looked like it started just below the line of combined height of a single arrow and the thumb. Yet, the clicks on the content acted as if the content started at the proper place - the top of the widget.
...OK, I found that out yesterday and it seems I've already forgotten why I did I called that 'a rounding problem' (cause it wasn't just a random thought)...will write more once I remember.
One more thing (but this might be already fixed, as I'm still on 2.22): the content tooltip interacts weirdly with scroll bar. While the tooltip itself is quite small, it seems to cover a part of the treeview by an invisible window, that prevents thumb being redrawn as it passes through the covered part - once it passes that area or the tooltip is triggered on a different part of the treeview, the thumb will be redrawn correctly.