If it's a Java game, you'll need to switch back to the 32-bit version of Firefox. The 64-bit version only enables the Flash and Silverlight plugins.

But I think wmode is a Flash parameter. Do you have the 21.0.0.213 update for Flash? My plugin lister page is an easy place to view plugin versions:

https://www.jeffersonscher.com/res/plugins.html

You can get the latest "full" installer from this page (on the Firefox row, either EXE or MSI will work): https://www.adobe.com/products/flashplayer/distribution3.html

It's a flash game, it's been working for years even after upgrading to FF 64. I have the latest Flash same as you. I don't see any vmode option in the flash options

The wmode parameter is usually part of the URL of the Flash media, or one of the parameters. It's not something that users control, as far as I know.

https://helpx.adobe.com/flash/kb/flash-object-embed-tag-attributes.html#main_Using_Window_Mode__wmode__values_

Could Firefox's Tracking Protection feature be a factor? If Tracking Protection is being applied, there will be a small shield icon in the address bar near the padlock icon. You can click that icon to turn it off temporarily to see whether that makes any difference. More info in this article: What happened to Tracking Protection?.

I have tried turning the tracking protection on and off does not have any affect.

Most FB games are embedded in a frame. Is there any way to try to play the game on the game publisher's site to see whether that works around the problem? You could try the following, although it doesn't always work: right-click the embedded page, then click This Frame, then Open Frame in New Tab.

Have tried opening the frame in a new tab or window, doesn't work.

Could you mention what game it is in case someone can go into FB and try it?

First one was Angry Birds Friends. Clock Maker also doesn't work anymore although it's error is different Context3D not available! Possible reasons: wrong wmode or missing device support.

Hmm, missing device support could be a problem with hardware acceleration, in other words, the compatibility of Flash and Firefox with your graphics card/chipset driver software.

You may want to check whether graphics card/chipset driver updates are available for your system. This article suggests safe ways to do that: Upgrade your graphics drivers to use hardware acceleration and WebGL.

Also, I don't know whether this is a new issue with Firefox beta. You might try switching to the release version (Firefox 46.0.1). You can grab the full installer from this page (scroll down to your preferred language): https://www.mozilla.org/firefox/all/

It only required me to go back to the non beta channel, something about the beta screwed things up even though I have been on the beta channel since they released a 64bit version

I am running 64 bit Windows 7 with a Windows 10 upgrade. Sometimes my Keyboard will not work when I am online but in particular I have noticed it mainly happens when I am playing "Goodgame Empire", "empire.goodgamestudios.com". I have not figured out what causes it to happen but I have discovered a way to work around the problem. Maybe this will also work for you........ On the Menu Bar click on: Tools > Web Developer > Style Editor or if it will allow you to use the shortcut key: Shift F7 The editor loads at the bottom of the page and then it will allow me to use the keyboard. Most of the time I can then click on the X to close the editor and it still allows me to use the keyboard.

I have not tried to play any games on Facebook for many years but I suspect it might work for you also.