Bug 1957280: Limit user's mouse amount for tree component r=places-reviewers,reusable-components-reviewers,masayuki,mstriemer
Differential Revision:
https://phabricator.services.mozilla.com/D251224
<!DOCTYPE html>
<title>CSS Scoping: Shadow host is featureless</title>
<link rel="help" href="https://drafts.csswg.org/css-scoping/#host-element-in-tree">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="host">
<template shadowrootmode="open">
<style>
div {
--x:FAIL;
}
</style>
</template>
</div>
<script>
test(() => {
assert_equals(getComputedStyle(host).getPropertyValue('--x'), '');
});
</script>
