neear the top of the float.php page, you should see the following:
$remove = array();
$remove[] = "";
$remove[] = "x";
$remove[] = "y";
you can add any form element to this array to have it removed. For example if you have a form element named "myElement" and you want to add it to the array:
$remove = array();
$remove[] = "";
$remove[] = "x";
$remove[] = "y";
$remove[] = "myElement";