Popper dropdown for select positioned incorrectly after resize

I was only able to reproduce this on FF (on macos). After resizing the browser window to the left, with the select dropdown open, sometimes the dropdown is sometimes positioned too far too the left (16px):

Hendrik and I looked at this for a moment, but weren't able to find out what exactly's causing this. We were thinking that it might be the event listeners and resize observer competing (or the rerenders due to the changed menuwidth interfering). There seems to be some sort of race condition somewhere, because it doesn't occur every time.

One thing that I did notice is that setting placement to bottom-start does resolve the placement inaccuray when resizing to the right, so it's just resizing to the left that doesn't work after that.

I've moved it to 5.1.0. I wouldn't be surprised if this has been resolved by the changes we've made in the meantime, and it's not critical to ship this with v5.0.0 in my opinion.

[varl]

Re-report in JIRA if it is something that we want to fix. 16px sounds suspiciously like the window is going from without a scrollbar to with a scrollbar as you are making the window narrower.