Audacity 2.2.1 Empty dialogs

On MacOS 10.13.3, with Audacity 2.2.1, if I choose “Open”, a completely black dialog appears
When I choose Export (any format), a system gray dialog appears, but no contents.
I can close both dialogs by pressing the Esc key.
All other dialogs are fine.
I can open a file by dragging it to Audacity, but these 2 options are not usable.
I tried to reinstall Audacity, deleting ~/Library/Application Support/audacity, but it still doesnt work.

What can I try to solve this?
Thanks,
Stephan

PS: strange: in the screenshot I made of the Open Dialog, it appear empty, but not black
Screen Shot 2018-02-08 at 01.01.15.png
Screen Shot 2018-02-08 at 01.01.33.png

Well, a reboot fixed it.

Weird.

Indeed.
– Bill