i have a soluition, not the best way – but it works.
if someone want the same, just add this after tbody in
flamingo/admin/includes/meta-boxes.php line 163:
<script>
jQuery(document).ready(function() {
jQuery('table tr.alt').each(function(){
var hide = true;
jQuery('td.field-value',this).each(function(){
if (jQuery.trim(jQuery(this).text()) != "")
hide = false;
});
if(hide)
jQuery(this).closest('tr').hide();
});
});
</script>