I have replaced
this.fallback = false;
to
if (navigator.appName == 'Microsoft Internet Explorer') {
this.fallback = false;
} else {
this.fallback = true;
}
In the class/js/aardvark. php to fix firefox issue and keep default setting for IE. Also, now helpcenterlive works fine in Opera browser too.
This option works fine in IE 7 and FireFox 3. 0. 7. Thanks.
I made the changes above, and that fixed the issue for me in firefox for both admin, and customers being able to use firefox.