Mason Freed

> `:top-layer` is like `*:top-layer` where `*` matches elements, not pseudo-elements like `::backdrop`. Do you mean `::backdrop:top-layer` should match? But that's strange, because pseudo-elements can only be followed by user...

> I think the word `layer` should maybe be "reserved" only for things relating to cascade layers, as I believe this can cause confusion I see the point - suggestions...

> This is to prevent a random element outside the top layer with z-index: 999999 to appear above a `::backdrop`. Right, or if you have nested popups/dialogs. The backdrop from...

> And that the top layer can consist of _multiple_ elements. Nested elements is the answer here too. It's a semi-common use case. Like a dialog that has a tooltip...

> I don't think it's a concept that speaks for starters/most people. Web devs know that a certain element is fullscreen, or a certain dialog is open/modal. Blog posts might...

> Your comment seems to suggest otherwise, `:top-layer` doesn't match during the closing transition, even though the popup is still in the top layer when closing. I think it makes...

Per the last CSSWG call about this issue, I was tasked with taking this issue back to OpenUI for further discussion. We did that on July 14. See the notes...

> If we have an `:open` pseudo-class, it should mean that something is 'open', (and I agree that it should apply to anything that can be open, like ``). This...

I'm hoping we can discuss this at the next CSSWG call. It sounds like we might be approaching a consensus on the thread to use `:open` as the pseudo selector...

> Hmmm, while I don't like bikeshedding forever, I think I can be pretty happy with `:open`. Seems like it hits a clear and reasonably obvious semantic, and applying to...