Enable multiple selections from dropdown

When you turn on the search box with taxonomy/attributes or customer field dropdown menu, by default you can select multiple values for filtering. Take a look at the below image.

If you want to turn on multiple selection values, use our 'wpto_is_multiple_selectable' filter hook.

Add those codes to your theme/child theme's functions.php file or use the 'Code Snippets' plugin to add those codes.