Yeah, the forum software likes to do that. If you hover over the link, it will give you a context menu where you can choose "bare URL" or something like that...
The current release of Flash Player is 22.214.171.124. The current Firefox ESR is Firefox 60.8.0, and the current generally available version is Firefox 68. Flash Player and Firefox are interdependent, and running arbitrarily mismatched versions is not a recipe for success. At minimum, you should run the latest ESR version.
Flash Player 126.96.36.199 has been out since October 8th, and I'm not seeing widespread reports of performance issues.
Also, if you haven't rebooted since you started encountering performance issues, that's a great place to start. "When in doubt, reboot" is still great advice in 2018, and at minimum, eliminates a whole host of potential causes.
I'm the OP. I had to re-register because the forum wouldn't accept my PW, then not again after resetting.
I reboot every morning.
I have the latest esr, 52.9 ESR. They're not arbitrarily mismatched versions. Millions of users are staying with ESR because they don't want to lose all their extensions. I'm not alone in this.
I first posted this problem on Mozillazine, the best forum for Mozilla products. I tried it in Firefox Safe-Mode too. It was decided that they should work together, and I was asked to try this forum.
I have the latest FlashPlayer, and I get updates automatically. The problem exists only in the version I posted on Nov 7, and the one that arrived today.
Flash has a long and miserable history of causing problems with Firefox, which is why Mozilla will be dropping it entirely soon. It has already dropped all its other plugins and incorporated their functions into its own code.
Although the problem isn't widespread, maybe you can shed some light on it.
The current Firefox ESR is Firefox 60. https://www.mozilla.org/en-US/firefox/organizations/
I'm unable to reproduce the performance issue you're describing, so I can't really shed any light on it.
My recommendation is to upgrade to the current Firefox ESR and current Flash Player (I provided the wrong version number earlier -- the current version is 188.8.131.52) and see if the performance issue persists.
It would also be useful to know if you're on 32 or 64-bit Windows, and whether you're running 32 or 64-bit Firefox, as that could be in play.
Also, if the long and miserable history of Flash Player is proving too burdensome for you, you're always welcome to uninstall it and find non-Flash alternatives for those games. I've included a link to the uninstaller below for your convenience.
Uninstall Flash Player - Windows:
I'm on a Win7-64, with a 64 FF. I'll try the 60, if I can still keep my extensions. thanks.