[gentoo-user] Strange flashplayer behavior recently

[walt]

I'm always getting email with links to youtube and various
other flash-intensive websites, and just a few days ago the
flash content stopped loading in firefox when I click on the
URL in thunderbird.

For example, the youtube web page opens normally and all the
various icons come up, but the video window just stays black
instead of playing the video.

If I then use the same firefox session to visit other websites,
their flash content doesn't load either.

Here is the really weird part: if a firefox window is *already*
open when I click the URL in thunderbird, all the flash stuff
comes up normally in the existing firefox window :-/

Using ps to examine the firefox process shows the URL to be
exactly the same as if I start firefox from a command prompt,
so thunderbird isn't corrupting the URL that it passes to
firefox.

As I said, this problem started just recently, after working
correctly for years.

I'm stumped.  Any thoughts?