This is great, makes the demo work just like you'd expect. Should MenuAnchor take care of disabling web context menus (perhaps optionally) itself?

Should MenuAnchor take care of disabling web context menus (perhaps optionally) itself?

No, because we can't know what they will bind to opening the menu. It doesn't make sense to disable it unless it's using the same key/button binding as the browser menu.

Good point. Still, using the same event as the browser to trigger opening the menu is likely to be a common case, so we're making writing portable code a bit more tedious. What if MenuAnchor set up itself up as a right-button context menu - with the platform-specific triggering event tweaks from your example - and disabled the browser menu by default. And we allowed developers to easily defeat the default behavior?

We could make a constructor for MenuAnchor that did that for you, perhaps, but MenuAnchor is a general purpose menu class, not just for context menus. Could be that you just want it to open a menu on a dropdown, and you don't want it disabling the browser context menu in that case.

I think including it in an example does at least help surface it, although it would be better in the docs, and maybe a special constructor for context menus.