I have three monitors 2 1920x1200 and my laptop screen which is 2560x1440 with display scaling at 200%.
On the laptop display with displayfusion running if I over over a table or a link with a tooltip it appears for a second or so and then disappears. Similar things happen with javascript based navigation like the one on this site. If I hover over downloads the menu drops down but then disappears making it really hard to get to one of the menu items. If I exit displayfusion the problem goes away.

Oh... Also I just tried changing my DPI scaling to 100% and the problem goes away too!
No problem at 125% or 150% either. 175% and 225% both have the issue as well.
And...If I set one of my 1920x1200 monitors to 200% display scaling the problem is there as well.

So I guess its a display scaling issue ?
I'm running the latest beta.

Yes that fixed it!
I can live without buttons.
Thanks!