Suggestion

If you do not want the Product Listing Filter dropdown to show when you have less than or an equal number of products to display
than your Admin > Configuration > Product Listing > Product Listing - Columns Per Row setting, if set greater than 1,
and when Use Product Listing Filter for "WHATEVER Products" in SNAF is set to True -

In \includes\modules\YourTemplate\product_listing.php
change Lines 313-318 (SNAF 1-2)

Code:
if($show_product_listing_filter)
{
require($template->get_template_dir('/tpl_snaf_display_order.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_snaf_display_order.php');
}
to

Code:
if($show_product_listing_filter and $listing_split->number_of_rows > 1)
{
require($template->get_template_dir('/tpl_snaf_display_order.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_snaf_display_order.php');
}