First of all I see much smoother rendering when using the DMABUF WebGL backend with Webrender on google maps and other modern maps that use WebGL.

There is one regression I experience however, and that is dragging of the map does not work any more. STR:

• go to maps.google.com
• try to drag the map around

Expected result:

• it works

Observed result:

• nothing happens

That's interesting, I'll look at it. BTW. this is still off by default.

Robert, which backend do you use - WebRender or GL?
And also which mutter version do you use? I can't reproduce it on Fedora 31 / mutter-3.34.4-1.fc31.x86_64 with both GL and WebRender compositor.

Webrender with GS/Mutter master.
But I just retested and it turns out it does not have anything to DMABUF Webgl backend, although it totally appeared to me in the beginning: apparently DnD completely breaks on Mutter master in regular intervals and I can simply drag nothing, neither a map nor an image or text. So I'll go on and try to debug that :)