From bug 776054 comment 1, roc said: > Off-main-thread-animations are going to cause problems wherever we've got an > nsDisplayTransform that combines a transform due to CSS styling with another > transform (e.g. a transform imposed by SVG viewbox or 'transform' > attribute). A CSS animation on such an element will modify the layer's > transform directly, wiping out any modifications made by SVG. > > To fix this, we should ensure that CSS transforms aren't mixed with other > transforms in the same nsDisplayTransform. We may need to create multiple > nsDisplayTransforms for the same element. That's OK as long as they always > have different display-item-keys.

Not sure if this is the right bug for this link, but.. Per https://webcompat.com/issues/148 the URL https://s3-us-west-2.amazonaws.com/demos.boxviewapi.com/3d.html has worse performance in Firefox than others. It seems be due to a combination of SVG content and CSS transforms. Does this seems like a known bug, or should we report one?

Please report another one, Hallvord. Thanks!

Thanks, bug 1194187 for follow-up