Layout. Firefox ignores position:fixed if the parent has blur. What to do?

Question

css

Codepen
codepen.io/MrCheater/pen/BzQymN The whole point of the HTML
problem

<div class="firefox-gavno">
  <div class="test-firefox">Firefox gavno. Fixed block Bottom 30%</div>
</div>
<div class="test">Fixed block Bottom 30%</div>

css

body {
  padding:10px;
}

.test {
    position: fixed;
    bottom: 30%;
    background: red;
}

.test-firefox {
    position: fixed;
    bottom: 30%;
    left: 300px;
    background: green;
}

.firefox-gavno{
    filter:blur(0px);
}

Answer 1

Well, actually, firefox is just right, read the documentation (by the way, are you aware that this is only a draft?)
https://www.w3.org/TR/filter-effects-1/#placement
This is how transform works. In human language, the problem is described here: meyerweb.com/eric/thoughts/2011/09/12/un-fixing-fi...