can confirm this works (don't worry i didn't do a public post using it)
This is still a problem, bumping this as I think it has a lot of potential for harm.
this is Actually Fixed now -- the sanitization now blocks every value of `position` other than "static", "relative", "absolute", "sticky", "inherit", "initial", "revert", "revert-layer", or "unset" (case-insensitively.)
If you use a backslash \ in the "fixed" ( position:f\ixed ), you can bypass the position:fixed prevention and make any element fixed to the viewport.
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