Yes, i have the same problem. It seems to be Flash-related, but uninstall/reinstall of Flash doesn't change anything...

I too have the exact same problem. I hope someone here has or will submit this to the proper channels to have this resolved.

I got this problem too but i am on windows vista. It does not appear straight away. Typically if the browser has been left for open for a few hours then i open a new tab and go on youtube or something similar. Just the browser main window will go from aero to basic mode

I got this after FireFox updated its self to 3.6.6. The new version has this plugincontainer.exe file, that the older did have. This extension (?) that mozilla added, appears to be the problem. Although FF crashes less, the effect is the same. If the Aero gets disabled, people will restart the browser (so basically, the change only gives you time to finish what you were doing before restarting). Considering this wasn't happening before this change, and the only change is the upgrade, the issue is directly related to a programming error or, if you like: BUG.

I get this several times an hour. Directly related to flash enabled web site. And as many sites have flash, the experience with Firefox, makes me not want to continue using it. Each update of Firefox, makes it worse then it was before. How about testing the code before making it public. I'm not your damn beta tester!

sometimes when i open some new pages, the whole OS would turn to basic vision, and after few minutes, it returns.

Same here with Firefox 3.6.6. It doesn't get back to normal untill I shut down Firefox and open it again.. I know this started happening after Out-of-process-plugin (this is what plugin-container.exe is for) was added.

All the other windows stay normal when it's happening to Firefox, meaning that it doesn't disable Aero but just changes the appearance of the window.

Has anyone reported this bug to Bugzilla?

Yes, I have a similar problem - it happens also when I want to download something and have to choose where to save it or when I want to upload, for example, some pictures (the window that shows in those cases crashes Firefox and the theme returns to basic).

I am having this problem as well. I am running Windows 7 and using Firefox 3.6.8 I tried the first 4.0 beta, but it did it then as well. Only Firefox is affected and turned to windows basic. everything else remains in aero.

The same problem, but i have no idea whether it is related to flash. After a period of running firefox, it sometimes changes to windows basic theme itself. New opened firefox windows has aero, but the old ones still keep basic theme.

Same here on FF 3.6.8. Everything else is Aero except for FF. Started only recently.

Español ---> Generalmente me pasa cuando miro videos de youtube o tengo el facebook abierto y juego en facebook que pueda ser no se ....

English ---> Usually happens to me when I watch videos on youtube or facebook I have the game open and facebook that may be not ....

same, this is very annoying, and it started happening during some version update of 3.6 (maybe 3.6.4, 3.6.6, im running 3.6.10 and it still has this problem) Everything is on Aero, and when Firefox starts up it's on aero but when it gets stressed the window bar at the top turns to basic. ARRGH!

same, this is very annoying, and it started happening during some version update of 3.6 (maybe 3.6.4, 3.6.6, im running 3.6.10 and it still has this problem) Everything is on Aero, and when Firefox starts up it's on aero but when it gets stressed the window bar at the top turns to basic. ARRGH!

It happens that give added plugin-container.exe

Same problem, very annoying , but now i'm using Opera and everything is ok....

I think i have found the solution! i have opened and closed Firefox (Firefox 4) 3 times while open Youtube video and other flash video and the Aero theme hasn't changed to basic.

Basically i downloaded and installed again adobe flash player, but i chose other operating system and chose my os and other browser (its either IE or other browser) for step 1 and step 2, respectively.

Adobe Flash Player: Other Operating System (Download page) Direct Link: http://get.adobe.com/flashplayer/otherversions/

Hopefully it'll work for you.

Update: Worked fine until I put it to full screen which caused it to go to basic.

Update:used about:config and toggled dom.ipc plugins and it works, but heard it will effect some performance of browser is that true? Guess I'll continue to use it with the plugin container disabled to see if i notice any performance deterioration.

Update:The browser became really slow.