Could you describe what you mean by "fog over" in more detail?

When a tab crashes, you usually see a white background with a loading animation circle in the center of where the page should be. Is that the problem?

"Fog over" means exactly what it sounds like; suddenly that active window is blurred/fogged over so what's *supposed* to be visible there, isn't. I've not noticed a loading animation circle, and the effect I *am* noticing is the entire active window is obfuscated, like looking through a (dense) cloud.

(Happens every few days and I've never found a way to recover consistently; typically I have to explicitly re-visit the page; "refresh" does not help at all.)

Hmm, do you use an ad blocker? Many sites have an overlay in front of the page with a message about subscribing or something, and an ad blocker might remove the message without removing the overlay. You could try making an exception for the site in your blocker(s), reload the page, and see what appears.

No ad blocker.

It can happen on "any" site - so it must be a Firefox issue (or some add-on, but my only substantial add-on is NoScript).

Occurs at random, often a day or two between events. It happened *right here,* on this Support page/form, just a few minutes ago.

BillM said

NO AD BLOCKER. It can happen on "any" site - so it must be a Firefox issue (or some add-on, but my only substantial add-on is NoScript).

Occurs at random, often a day or two between events.

I know about the 'Fog' you're talking about. It's like milk spilled over the screen and you can still see the page, but it's like seeing across the street - buildings still seen through the 'Fog'.
Again... it's MEMORY related. While I did have Fog issues with IE and pre-Quantum FF, I've seen it briefly at times with FF Quantum.
However, I saw more Fog and FF hangups with that NoScript Extension! My many FF problems went away when I got rid of NoScript.
It can get 'crossed-up' and conflicted, mess-up browsing and rob Memory and it produced more Fog screens than ever before. It's like you need training and a 'Pilot License' to use NoScript. It's not for the everyday FF user, is what I'd say.
I'd highly suggest you get rid of NoScript and use UBlock Origin (More Memory-Friendly than AdBlock Plus).
Oh, NoScript also can do Ad-Blocking.

~Pj

I would concur that NoScript is not for newbies; I'd classify it as a toolbox rather than an end-user solution, but it's the proverbial "devil I know."... and well-supported by the author at noscript.net .

When you say the fog is memory-related ... do you mean total available memory for the process, or memory corruption? (My newer laptop only has 3GB, and does "get foggy" more often, to be sure.)

BillM said

...Well-supported by the author at noscript.net .

It may be 'Well-Supported' but it was a headache for me. (Grin)

My newer laptop only has 3GB, and does "get foggy" more often, to be sure.

Yeah, 3GB is pretty thin for nowadays. I had long-running Fog-Freezes when I had NoScript. I haven't seen any major Fog issues for many months now since I dumped NoScript.
AdBlock Plus had its problems, too (like Memory-Hogging at times). uBlock Origin is working much better for me. (Wink)

~Pj

I've been wanting to add memory; 8G is the max on my Win7 laptops. My older one has 4G, but its own set of issues since I froze its WinUpdates in time, to keep WinX from "taking over."

I hardly ever get real *freezes* (a/k/a lockups) where the system literally won't do anything without rebooting.

UPDATE re fog-over ... it is NOT a Firefox-unique problem.

Quite coincidentally, I experienced the same behavior on Chrome tonight.

(That doesn't solve it, or even suggest a resolution path, but it's the first time I've seen it outside Firefox... so it's more likely to be an idiosyncracy of the web page.)

It is, in any event, rare. I'll start watching for a recurrence (with any browser) and attempt to capture the page source.

BillM said

UPDATE re fog-over ... it is NOT a Firefox-unique problem. Quite coincidentally, I experienced the same behavior on Chrome tonight...

Memory. If using NoScript... more problematic and Memory. (Grin)

~Pj

Hmm, color me skeptical... since the "fog effect" *itself* adds to the memory and CPU burden of rendering the page ;)