[dreamer_]

For me, it works perfectly on both FF and Chrome (Linux), but I wonder how WebRender will deal with it; can you test Firefox Nightly with "gfx.webrender.all" set to true?

[thirdsun]

Thanks! gfx.webrender.enabled (not .all) alone does indeed solve the performance issues, however only in Nightly (v62), not in the Beta (v61) channel.