Accelerated composition was added as an experimental feature in JavaFX 11 by JDK-NNNNNN. It is disabled by default and enabled by setting the boolean system property "com.sun.webkit.useCSS3D" to "true". It currently fails to render properly, likely due to a change in the underlying WebKit implementation that wasn't taken into account. Since we have no tests for this (see JDK), we didn't notice it until recently.

If you run any of the following sites, it fails to render correctly:

https://webkit.org/blog-files/3d-transforms/poster-circle.html
http://is-real.net/experiments/css3/wonder-webkit/
https://webkit.org/blog-files/leaves
https://desandro.github.io/3dtransforms/examples/cube-02-show-sides.html
https://webkit.org/blog-files/3d-transforms/morphing-cubes.html
https://davidwalsh.name/demo/css-cube.php
https://www.smashingmagazine.com/2016/07/front-end-challenge-accepted-css-3d-cube

There is also a report of a crash in some cases, but I haven't seen one.