Firefox problem resolved.
It appears both problems are better. For firefox, I followed the
instructions in reportbug and removed all plugins (there were only two).
So far firefox is stable. There was a flashplugin that might have been
causing the problems.
After a fresh install of amd-64 gnome panels blink for a while and
then die. KDE seems fine.
Firefox dies intermittently when I click on the return button. When I
launched from the command line, I get many errors such as this one.
(Gecko:3550): GLib-GObject-CRITICAL **: g_object_unref: assertion
`G_IS_OBJECT (object)' failed
In this case, it died with this message:
The program 'Gecko' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadShmSeg (invalid shared segment parameter)'.
(Details: serial 32 error_code 165 request_code 143 minor_code 2)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error()
Anyone else seeing this?