Hi Panos. I used:
echo "<label for='genre'>Genre:</label>";
$sc_ajax_select_boxes->show_select_box('genre');
echo "<br /><label for='singer'>Singer:</label></p>";
$sc_ajax_select_boxes->show_select_box('singer');
The first time when I had the problem I used the variable: $sc_ajax_select_boxes. The proper way was to use them before the variable show_select_box('').
Hope it's clear.
