diff --git a/js/_frontend.js b/js/_frontend.js
index b4bb8cf..f126783 100644
--- a/js/_frontend.js
+++ b/js/_frontend.js
@@ -69,7 +69,7 @@ const wpdtrtAnchorlinksUi = {
         let anchorTextAbbreviated;
         let stickyTitle = '';
 
-        if ($anchor.length && $anchor.find(highlightController).length) {
+        if ($anchor.length && $anchor.is(highlightController)) {
             anchorTextAbbreviated = $anchor.find('h2').attr('data-abbreviation');
 
             if (anchorTextAbbreviated) {
@@ -109,37 +109,6 @@ const wpdtrtAnchorlinksUi = {
         }
     },
 
-    /**
-     * @function injectListAdditions
-     * @summary Append theme elements after the list, in the order specified.
-     * @memberof wpdtrtAnchorlinksUi
-     * @protected
-     *
-     * @example
-     * <div data-wpdtrt-anchorlinks-list-addition="1" data-wpdtrt-anchorlinks-list-addition-clone="false">Added first</div>
-     * <div data-wpdtrt-anchorlinks-list-addition="2" data-wpdtrt-anchorlinks-list-addition-clone="true">Added second</div>
-     */
-    injectListAdditions: () => {
-        const $ = wpdtrtAnchorlinksUi.jQuery;
-        const $elements = $('[data-wpdtrt-anchorlinks-list-addition]');
-        const $block = $('.wpdtrt-anchorlinks');
-
-        $block.append('<div class="wpdtrt-anchorlinks__additions"></div>');
-        const $additions = $('.wpdtrt-anchorlinks__additions');
-
-        $elements.each((i, item) => {
-            let id = i + 1;
-            let $orderedAddition = $elements.filter(`[data-wpdtrt-anchorlinks-list-addition="${id}"]`);
-            let clone = $orderedAddition.attr('data-wpdtrt-anchorlinks-list-addition-clone');
-
-            if (clone === 'true') {
-                $orderedAddition.clone().appendTo($additions);
-            } else {
-                $orderedAddition.appendTo($additions);
-            }
-        });
-    },
-
     /**
      * @function setListMaxHeight
      * @summary Calculate the height available to the anchor list.
@@ -362,8 +331,6 @@ const wpdtrtAnchorlinksUi = {
             pinController: $('[data-wpdtrt-anchorlinks-controls="pinning"]')
         };
 
-        wpdtrtAnchorlinksUi.injectListAdditions();
-
         wpdtrtAnchorlinksUi.sticky_jump_menu($('.wpdtrt-anchorlinks'));
 
         console.log('wpdtrtAnchorlinksUi.init'); // eslint-disable-line no-console
diff --git a/template-parts/wpdtrt-anchorlinks/content-anchorlinks.php b/template-parts/wpdtrt-anchorlinks/content-anchorlinks.php
index 1a2bbfb..fc99a62 100644
--- a/template-parts/wpdtrt-anchorlinks/content-anchorlinks.php
+++ b/template-parts/wpdtrt-anchorlinks/content-anchorlinks.php
@@ -18,8 +18,9 @@
 $after_widget  = null; // register_sidebar.
 
 // shortcode options.
-$post_id    = null; // $post->ID stand-in for unit tests
-$title_text = null;
+$post_id         = null; // $post->ID stand-in for unit tests
+$title_text      = null;
+$additional_html = null;
 
 // access to plugin.
 $plugin = null;
@@ -31,6 +32,10 @@
 // @link http://kb.network.dan/php/wordpress/extract/.
 extract( $options, EXTR_IF_EXISTS );
 
+// if ( null !== $additional_html ) {
+// 	$additional_html = esc_html( $additional_html );
+// }.
+
 global $post;
 
 if ( isset( $post ) && is_object( $post ) ) {
@@ -58,6 +63,10 @@
 	<?php endif; ?>
 	<?php
 		echo $plugin->render_anchor_list_html( (array) $anchors );
+
+	if ( null !== $additional_html ) {
+		echo "<div class='wpdtrt-anchorlinks__additions'>{$additional_html}</div>";
+	}
 	?>
 </div>
 
diff --git a/wpdtrt-anchorlinks.php b/wpdtrt-anchorlinks.php
index 85c4e62..47fa1f3 100644
--- a/wpdtrt-anchorlinks.php
+++ b/wpdtrt-anchorlinks.php
@@ -211,6 +211,13 @@ function wpdtrt_anchorlinks_plugin_init() {
 			'tip'     => __( 'e.g. Outline', 'wpdtrt-anchorlinks' ),
 			'default' => __( 'Outline', 'wpdtrt-anchorlinks' ),
 		),
+		'additional_html' => array(
+			'type'    => 'text',
+			'size'    => 30,
+			'label'   => __( 'Additional HTML', 'wpdtrt-anchorlinks' ),
+			'tip'     => __( 'Added in .wpdtrt-anchorlinks__additions', 'wpdtrt-anchorlinks' ),
+			'default' => __( '', 'wpdtrt-anchorlinks' ),
+		)
 	);
 
 	/**
@@ -297,6 +304,7 @@ function wpdtrt_anchorlinks_shortcode_init() {
 			'selected_instance_options' => array(
 				'post_id',
 				'title_text',
+				'additional_html',
 			),
 		)
 	);