<!DOCTYPE html> <html lang="en" class="reftest-wait"> <meta charset="utf-8"> <title>Both divs should be part of opaque layers in the final paint.</title> <style> .content { box-sizing: border-box; width: 200px; height: 200px; border: 1px solid black; } .fixed { position: fixed; top: 20px; left: 140px; } .opaque-background { background-color: white; } .reftest-wait .opaque-background { /* make the layer start out transparent */ background-color: transparent; } body { height: 4000px; } </style> <div class="content reftest-opaque-layer"></div> <div class="fixed opaque-background content reftest-opaque-layer"></div> <script> function doTest() { document.documentElement.removeAttribute("class"); } document.addEventListener("MozReftestInvalidate", doTest, false); </script>