I run Firefox ESR on Debian 12. X11. Plasma 5. “128.10.0esr (64-bit)”.
It has this infuriating, randomly but frequently occurring visual glitch, which also happened earlier when I was using ungoogled-chromium (before switching back to Firefox due to literally having no other choice).
It’s difficult to explain, but randomly when loading any webpage or opening/closing any tab, it “flashes” the screen with either a white or dark frame just before painting the actual, sharply contrasting, background. I’ve tried countless times to reproduce it reliably, but it seems completely random, and is driving me absolutely insane.
This does not happen with any other program besides the two web browsers and specifically the program pgAdmin 4, which uses Chromium for rendering. I don’t get “flashes” or any other kind of visual glitches in the graphical environment; it’s entirely isolated to Firefox and Chromium-based programs.
This is very bizarre because the two browsers are completely distinct and don’t share the same underlying rendering engine.
I tried insane hacks found online to put in userChrome.css/userContent.css but this made no difference. I’ve since removed them.
In Firefox’s “Performance” settings, I’ve tried unchecking both “Use recommended performance settings” and “Use hardware acceleration when available”, or one of them. Also tried setting layers.acceleration.disabled to true. No difference.
I’ve recorded my screen and watched the resulting video in slo-mo/frame-by-frame to verify that this is actually happening and isn’t something I’m imagining. Sure enough, it renders one frame of the opposite colour instead of “remembering” whatever background it’s currently displaying until it’s ready to display the new one.
My desktop theme is set to dark and Firefox is set to prefer dark theme on webpages, but this means nothing. Many websites don’t support this automatic “theme” detection, and it seems to have nothing to do with this anyway. Whether the real webpage is bright white or very dark, there is one frame of “opposite color” flashing randomly. And I cannot stress enough that it does not happen every time! Some unknown variable/“state” is causing it to happen.
Since I’ve extensively researched this before asking here, I’ve found very concerning and old discussions on what appears to be related to this, of course with no solution or fix ever appearing. I refuse to believe that this is really the case, though. I must be missing something. There has got to be an easy fix. There is no possible way that everyone using Firefox on Linux is experiencing and putting up with these “flashes”.
What is causing it? Why does it appear randomly? How do I make it stop? If it actually is somehow related to my “GPU drivers”, why would it only happen in Firefox and not also programs such as the text editor Kate or the Dolphin file manager, etc.?