Xlib: extension "Generic Event Extension" missing on display "localhost:11.0"

[Dave Howorth]

I've recently installed karmic onto a test machine and I'm presently
running programs on it via the display of my regular machine after
logging in via ssh -X.

When I run Firefox for example I see many messages like this on the
controlling terminal:
  Xlib:  extension "Generic Event Extension" missing on display
"localhost:11.0".

I'm wondering if anybody has come across this problem and knows how to
fix it?

My regular computer runs an embarrassingly old system so it wouldn't
surprise me if its X server is missing some feature. But an X client
should be designed to run against any X server and it certainly
shouldn't be spewing lots of repetitive messages.

I've found a little information about the error message, such as the
thread at http://ubuntuforums.org/showthread.php?t=1133105 but I have
libxcb-event1 installed on the karmic box and libxcb-event0 is not
available from the default repositories, so I suspect that thread is out
of date.

There's also a more recent redhat bug report -
https://bugzilla.redhat.com/show_bug.cgi?id=478607 - that mentions
libXext but I have the most recent version of that installed.

Thanks for any pointers,
Dave