Problem clearing gl3d scene with transparent background

[archmoj]

Tweak camera projection type on scene with transparent background makes the background darker!
codepen.

[archmoj]

Also if I create a 3-D scene with transparent blue background, it does not display blue: demo. However; making a png image works as expected.

[archmoj]

This is clearly related to using premultipliedAlpha: true instead of false.
cc: #4236
But instead of disabling it as suggested in #4280 i.e. only for FireFox, it demonstrates that the problem may also show up on other Browsers e.g. Chrome.

[gvwilson]

Hi - we are currently trying to tidy up Plotly's public repositories to help us focus our efforts on things that will help users most. Since this issue has been sitting for several years, I'm going to close it. If it's still a concern, we'd be grateful if you could open a new issue (with a short reproducible example if appropriate) so that we can add it to our backlog. Thanks for your help - @gvwilson