Editing Nav Dropdowns for mobile sizes not working

I’ve been creating a new site. I started as usual with adding a nav, putting into it some nav dropdowns and nav items.

Oddly, when I switch the editor to the smaller viewports (mobile style navs), the dropdowns still show as dropdowns for desktop viewport sizes!

If I am in preview mode, this doesn’t happen, if I publish it doesn’t happen.

What it means is that styling the nav properly for the smaller viewports is impossible to do in a WYSIWYG manner. I have to rely on the element navigator and my knowledge of whats what to do all the styling by guesswork and jumping back and forth to preview!

This is on Chrome, on Safari, all updated to latest versions and on multiple computers.

If anyone wants to replicate, add a nav, left to right have three dropdowns with some items in them, and three more nav items. Voila, webflow editor all messes up when you switch to a smaller viewport and then click the burger icon and show the expanded nav menu.