For a little while now, I've been getting this error: kdeinit4: preparing to launch /usr/bin/firefox Gdk-ERROR **: The program 'firefox' received an X Window System error. This probably reflects a bug in the program. The error was 'BadWindow (invalid Window parameter)'. (Details: serial 9502 error_code 3 request_code 20 minor_code 0) (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() function.) aborting... /usr/lib64/firefox-3.5.4/run-mozilla.sh: line 131: 20670 Aborted "$prog" ${1+"$@"} sometimes, when trying to launch Firefox via a launcher in the panel. I do not get it when launching from a terminal. I also see the same problem with Thunderbird. Any ideas? Richard