[csswg-drafts] [resize-observer] Which boxes should we be able to observe?

gregwhitworth has just created a new issue for https://github.com/w3c/csswg-drafts:

== [resize-observer] Which boxes should we be able to observe? ==
In Sydney it was resolved that authors should be able to observe more than the content box of an element. That then leads to which boxes should be able to be observed. The initial ones were quickly agreed upon such as `border-box`, `content-box`, and `scroll-box`.

Is there any other boxes that people have legitimate use cases for observing?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3326 using your GitHub account