Mouse hover over partially displayed Library/Board Manager entry causes the scroll to jump up/down

Using Arduino IDE 1.8.6 Hourly Build 2018-07-19 10:33, Windows 10 64 bit

1. Sketch > Include library > Manage libraries...
1. Scroll down until only the first bit of the next entry shows at the bottom (this problem happens any time it's not scrolled to the "More info" line but this makes it more dramatic).
1. Move the mouse pointer over the portion of the bottom listing that's visible. The results scroll until the "More info" link is shown.
1. Move the mouse pointer to the portion of the top listing that's visible. The results scroll up until the "More info" link is shown.

Maybe this behavior is intentional. If so, I'd expect the listings to either jump scroll to show the entire next listing (which I'd still find distracting) or else do a slow continuous scroll (which is consistent with how the menus work but doesn't seem particularly useful in this case).


The same problem occurs in Boards Manager.

Reproduce the issue in the Arduino IDE 1.x Library Manager using the listed scroll and hover steps, then repeat it in Boards Manager. Start from the manager UI entry points reached through Sketch > Include library > Manage libraries; done means hovering partially visible entries no longer causes the results to jump unexpectedly in either manager.

Written by the indexing model from the issue text.