Bug tracker web interface sometimes records submissions twice (with

Does somebody know why firefox still allows the form to be submitted twice?  The page contains this code:


<script type="text/javascript">
submitted = false;
function submit_once() {
    if (submitted) {
        alert("Your request is being processed.\nPlease be patient.");
        event.returnValue = 0;    // work-around for IE
        return 0;
    }
    submitted = true;
    return 1;
}

function help_window(helpurl, width, height) {
    HelpWin = window.open('http://bugs.dragonflybsd.org/' + helpurl, 'RoundupHelpWindow', 'scrollbars=yes,resizable=yes,toolbar=no,height='+height+',width='+width);
}
</script>

....

<form method="POST" name="itemSynopsis"
      onsubmit="return submit_once()"
      enctype="multipart/form-data" action="issue1200">
....