User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2b1) Gecko/20091014 Firefox/3.6b1 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2b1) Gecko/20091014 Firefox/3.6b1 (.NET CLR 3.5.30729) The page that I'm viewing is not shown in the Windows 7 Powerbar preview. This happens with every YouTube video and occasionally with other sites. The preview just shows me the loading circle. Reproducible: Always Steps to Reproduce: 1. Open a random YouTube video 2. Hover the Firefox icon in Windows 7 Actual Results: The preview just shows me the loading circle. Expected Results: I expect to see the video playing in preview. about:buildconfig Source Built from http://hg.mozilla.org/releases/mozilla-1.9.2/rev/c60105da01a0 Build platform target i686-pc-mingw32 Build tools Compiler Version Compiler flags cl 14.00.50727.762 -TC -nologo -W3 -Gy -Fdgenerated.pdb -DNDEBUG -DTRIMMED -Zi -UDEBUG -DNDEBUG -GL -wd4624 -wd4952 -O1 cl 14.00.50727.762 -GR- -TP -nologo -Zc:wchar_t- -W3 -Gy -Fdgenerated.pdb -DNDEBUG -DTRIMMED -Zi -UDEBUG -DNDEBUG -GL -wd4624 -wd4952 -O1 Configure arguments --enable-application=browser --enable-update-channel=beta --enable-update-packaging --enable-jemalloc --enable-official-branding

i doubt the video can be playing in the preview being driven by a plug-in.

Why not? On http://tweakers.net/ I can see the flash banners moving...

Correction on first post: The fact that I see the loading-circle instead of the actual preview doesn't seem to have anything to do with YouTube. It seems to be random.. But the fact that I can't see the YouTube video playing in preview is always reproducable by just opening a YT-video.

Previews are not showing up in aero peek. I get the loading spinner and then a blank tab with an icon in it. The browser window flashes and shows a blank tab. No preview. Seeing this in: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2b2pre) Gecko/20091026 Namoroka/3.6b2pre (.NET CLR 3.5.30729) ID:20091026045753

also note that I had no plugins loaded on any of my tabs. I don't think that makes a difference.

Not sure what the STR for this are. I am not seeing this problem in a fresh profile after loading a few tabs. Restarting my browser with the initial profile and aero peek seems to work. I am using some unsupported extensions but they don't seem to be causing the problem even though they muck with the default theming. Adblock Plus 1.1.1 Ctrl-Tab 0.20 [DISABLED] Delicious Bookmarks 2.1.072 DownThemAll! 1.1.6 feedly 2.x Firebug 1.5X.0b1 Glasser 1.1.1 Html Validator 0.8.5.8 [DISABLED] IE Tab 1.5.20090525 Microsoft .NET Framework Assistant 1.1 myFireFox & Vista-aero Modifier 1.2.1 Nightly Tester Tools 2.0.2 Theme: Vista-aero

This is odd. Opening 30 tabs and Firefox gives up trying to do anything. Closing around 10 or so, and I see a list over the icon on hover. Closing another 10 or so, and I get the tab previews. These are heavy sites with a mix of plugin content and HTML and they seem to display fine. Still unable to reproduce the blank, spinning previews.