Should support for css scaling be extended to content with overlays?

Vaadin 8 does not currently support extensive css scaling in applications that use overlays, by e.g. giving a whole view or even the entire application a scale like .v-app { transform: scale(0.5) !important; }

With that kind of scaling the basic contents look and scroll just fine, but e.g. ComboBox, DateField, PopupView, and MenuItem popups (and quite likely other things that use overlays) misbehave/misposition themselves significantly (tested on Chrome, Firefox, and Edge on Windows 10). However, all of these things work just fine with browser zoom, and I don't recall hearing very many complaints about the lack of this kind of css scaling support, even if it's been missing for years. The purpose of this ticket is to document the missing feature, and to see if anyone would even be interested in getting it included. Those popup position calculations are quite tricky, so this might not be a trivial thing to do.

The issue identifies ComboBox, DateField, PopupView, and MenuItem popups as affected overlay components. Start by reproducing the reported behavior with a CSS transform scale on a Vaadin 8 view or application, comparing it with browser zoom. Done would require correctly positioning and interacting with overlays under CSS scaling across the reported browsers.