They are set to display:none, because the normal selects are only used to generate the JS based one. I will look into changing this and using JS to hide them, so if JS is not available they will show up anyway. But I think there was a problem with this, in a way that they where visible for a second and users saw the style being changed.
The current dropdown script is based on easydropdown, it grabs the values from the select and turns it into a group of
li items.
The easiest way to prevent the JS script from creating the custom dropdowns, is by removing the wpsl-dropdown class from the select items in the template code.
But since changing core files is generally a bad idea, you should copy the template you want to use, move it to your theme folder, and use this filter to define the new template.
Open the template file and remove class=”wpsl-dropdown” from both selects. You will have style the dropdown a bit to make it look good next to the search input field.
The category filter isn’t generated in the template file itself, so you will have to open the /frontend/class-frontend.php, search for function create_category_filter, copy the code inside that function.
In the template file that you moved to your theme folder, look for this code.
$output .= $this->create_category_filter();
Replace it with the code from inside the function create_category_filter, only replace all $category = with $output .=, and again remove the class=”wpsl-dropdown”.
The last step will be to add an extra CSS line to the styles.css in your theme folder that overwrite the display:none for the selects, and sets it to display:block