Firefox dogging lately after update

[Qqmike]

Lately following a Firefox update, the Firefox runs like a dog in some ways:

Annoying lags ...

Switching between tabs is slow:
After clicking on a tab to open, there is a lag (maybe 1-2.5 seconds) before it goes.
Running simple interactive games (slots, scratch cards, Lotto, etc.), it runs choppy, lags behind, doesn't quickly render new screens, and so on.
Scrolling up/down on a page may exhibit a lag.
Typing this post exhibits some lags (e.g., typing ***** shows a lag after typing ** until the last three asterisks appear.)

I didn't have these issues prior to the Firefox update.

Anyone notice this, too?

*****
Details:
Kubuntu 14.04 ...

 mike@mike-desktop:~$ inxi -Fxxx
 System:    Host: mike-desktop [B]Kernel[/B]: 3.13.0-101-generic x86_64 (64 bit, gcc: 4.8.4)  
            Desktop: KDE 4.13.3 (Qt 4.8.6) info: plasma-desktop dm: lightdm [B]Distro[/B]: Ubuntu 14.04 trusty

11/19/16 Update to Firefox (from Muon > View > History):
firefox (49.0.2+build2-0ubuntu.14.04.1,50.0+build2-0ubuntu0.14.04.2)Upgraded at 12:11 PM


Yes, I tried Chromium, it runs great, I had to use Flash with it to accommodate the site I was at ( https://wiki.ubuntu.com/Chromium/Getting-Flash ) . This Flash business gets confusing at times!

[GreyGeek]

No! I am running FireFox 50 and it is as fast as lightening! But, I have customized my preferences using the "about:config" setting.
http://kb.mozillazine.org/About:config_entries

https://support.mozilla.org/en-US/pr...x/fix-problems

[Qqmike]

GG, the first link is "Bad." But the second link looks good, and I will start working through the troubleshooting list as time permits. Thanks.

[Rod J]

@Qqmike:

I haven't had any of the problems you seem to be having but I did have a problem with Firefox 50 telling me libavcodec was needing to be updated (or words to that effect). It wouldn't play media in Twitter pages and some other stuff. I'm running K14.04 same as you. Apparently, an updated libavcodec isn't available yet in K14.04 repos.

I just went with the easy solution (a workaround) on this page. I quote the solution here:

"Just enable libavcodec in firefox:

type about:config in the address bar, enter

click "I accept the risk"

search for libavcodec

change media.libavcodec.allow-obsolete;false to true"

OK, I accept there is some tiny risk from doing that but I'm willing to take the chance. Hopefully the libavcodec will be updated soon.

[Qqmike]

I figured you'd be around Rod J (knowing you also ran 14.04). I tried what you posted, so we'll see. GreyGeek's link tells how to reset/refresh Firefox if need be

Thanks.

[GreyGeek]

Hmmm... This link works for me:
http://kb.mozillazine.org/About:config_entries

but when I paste it into this box it is mangled to be this:
http://kb.mozillazine.org/About<strong></strong>:config_entries
between the first two u r l boxe, which gives the 404 msg.
Manually removing "<strong></strong> " in the bad url allows it to work.

Here is a pic of what happens to the link:

[Qqmike]

OK, got it:
http://kb.mozillazine.org/About:config_entries
Thanks.

Rod J: I did have a problem with Firefox 50 telling me libavcodec was needing to be updated (or words to that effect)

Now that you mention it, I also recall such a pop-up message recently when I was working Firefox real hard.

[Snowhog]

Yeah, I'm experiencing the same behavior with that URL. I've returned your post back to 'as it was'.

[Qqmike]

GG: Ha! My link version in Post #7 was copied directly from the right site, but it also flips to being Bad when clicked! But at least we know The Truth now and can get there.

[Qqmike]

So far ...

I did a "Refresh Firefox," and it has helped a lot, it has solved many of the issues I was having. I have yet to really, fully test it, though; I'll report back after doing that someday soon.

fyi:
In Firefox, Help tab > Troubleshooting information --> Give Firefox a tune-up --> Refresh Firefox. That screen also lists everything about your installation of Firefox (your settings, your preferences, options, etc).

[Qqmike]

Looking at the description of
libavcodec-extra[-54]
in Muon, it does seem that it would help with the issues I listed in the OP--Firefox lagging, slow, choppiness in interactive audio-video sites. And installing it it did help. But it didn't do the whole trick. What finished the job was a Refresh of Firefox (see my post # 10).
I more fully tested Firefox this morning, giving it a heck of a workout (multiple tabs open, each containing audio-video interactive events), and Firefox seemed to perform very well (following the Refresh).

So, for now, I'll mark this Solved. Thanks Rod J for the tip re libavcodec. And links to Firefox troubleshooting are in GreyGeek's post #2. Thanks guys.

(btw, the site I refer to for a test is PCH.com, a reputable--though odds of winning are very low!-- sweepstakes/games site.)

[GreyGeek]

PHC -- Just like the lottery. You can't win if you don't play, but the odds are about the same.

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