Having this problem too, here is my post in case someone replies to that https://forums.opera.com/topic/43686/full-screen-sidebar-glitch?_=1600960754016

MacOS, OperaGX LVL2 (core: 71.0.3770.138), no extensions

Having this problem again, happened a couple updates ago as well but it was patched. When I put any videoplayer into full screen mode the slight purple effect of the sidebar is still there. Super annoying and takes away from any film or show I am trying to watch, anyone else have this problem/know a solution? It isn't visible when I take a screenshot.

I too have this problem, super small detail but so annoying.

When I put YouTube or Netflix into full screen, the visual gets cut in half and the halve swap, then the visual also goes sideways about 35 degrees to the right of how it normally is. When I move my cursor or hit any key it snaps back. I am using Opera Version:64.0.3417.61 and macOS Catalina v10.15. Anyone else having the same issue?

@archimdx I did, still have the problem. Same with youtube as well.

Hello all. I can now stream netflix and prime video but I am still having the problem that the film cuts in half and then switches sides in fullscreen. Anyone else have this problem? I can't attach a screenshot because as soon as you press any keys it goes back to normal for about 5 seconds.

I have the exact same problem! I have another problem which I think is related, whenever I try and watch youtube at full screen it goes diagonal and cuts the screen in half and switches the halves. Are you all having that issue too? I am running version 64 and Mac Catalina. Thanks!