[css-backgrounds][css-overflow] Is viewport's background painted behind viewport's scrollbars? #12744
Description
If both the background and the overflow get propagated to the viewport, what happens?
https://drafts.csswg.org/css-backgrounds-3/#root-background
https://drafts.csswg.org/css-overflow-3/#overflow-propagation
<!DOCTYPE html>
<iframe width="100" height="100" srcdoc="
<style>
:root {
background: cyan;
scrollbar-color: rgb(255, 0, 255, 0.5) rgb(255, 0, 255, 0.5);
overflow: scroll;
}
::-webkit-scrollbar { background-color: rgb(255, 0, 255, 0.5); width: 12px; height: 12px; }
</style>
"></iframe>| Gecko | Blink | WebKit |
|---|---|---|
 |
 |
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I would expect the background to be painted behind the scrollbar like in a normal element, and be able to change that with background-clip: content-box (but that never works, see #11169)