public static function sort_columns( $vars ) {
		// Check if we're viewing the "popup" post type
		if ( isset( $vars['post_type'] ) && 'popup' == $vars['post_type'] ) {
			// Check if 'orderby' is set to "name"
			if ( isset( $vars['orderby'] ) ) {
				switch ( $vars['orderby'] ) {
					case 'popup_title':
						$vars = array_merge( $vars, array(
							'meta_key' => 'popup_title',
							'orderby'  => 'meta_value',
						) );
						break;
					case 'opens':
						if ( ! pum_extension_enabled( 'popup-analytics' ) ) {
							$vars = array_merge( $vars, array(
								'meta_key' => 'popup_open_count',
								'orderby'  => 'meta_value_num',
							) );
						}
						break;
					case 'conversions':
						if ( ! pum_extension_enabled( 'popup-analytics' ) ) {
							$vars = array_merge( $vars, array(
								'meta_key' => 'popup_conversion_count',
								'orderby'  => 'meta_value_num',
							) );
						}
						break;
				}
			}
		}

		return $vars;
	}