I also reproduce this issue. This issue can be reproduced inside a brand new firefox profile as well as my current profile. All youtube videos, mac.com videos and google videos have this problem. I don't remember having this problem with Firefox beta 4. It happens with both metacity or compiz. Firefox gives a lot of relevant terminal outputs when I try to start a youtube video concerning murrine engine. Firefox outputs attached.
I also reproduce this issue. This issue can be reproduced inside a brand new firefox profile as well as my current profile. All youtube videos, mac.com videos and google videos have this problem. I don't remember having this problem with Firefox beta 4. It happens with both metacity or compiz. Firefox gives a lot of relevant terminal outputs when I try to start a youtube video concerning murrine engine. Firefox outputs attached.