Alternative for is_taxonomy() to workaround theme’s default sidebar
The function that replaces is_taxonomy() is named taxonomy_exists(). Than there’s also is_tax() and is_tag() that check if the query is for a taxonomy archive page. EDIT $selected_sidebar_replacement == ‘0’ || $selected_sidebar_replacement == ” won’t work. You’re not checking the type. Better do it like this: if ( ! $selected_sidebar_replacement OR emtpy( $selected_sidebar_replacement ) )