diff --git a/extensions/mentions/js/forum/src/addComposerAutocomplete.js b/extensions/mentions/js/forum/src/addComposerAutocomplete.js
index c6c9dd2c4..c65022744 100644
--- a/extensions/mentions/js/forum/src/addComposerAutocomplete.js
+++ b/extensions/mentions/js/forum/src/addComposerAutocomplete.js
@@ -107,7 +107,7 @@ export default function addComposerAutocomplete() {
                 .forEach(post => {
                   const user = post.user();
                   suggestions.push(
-                    makeSuggestion(user, '@' + user.username() + '#' + post.number(), [
+                    makeSuggestion(user, '@' + user.username() + '#' + post.id(), [
                       app.trans('mentions.reply_to_post', {number: post.number()}), ' — ',
                       truncate(post.contentPlain(), 200)
                     ], 'MentionsDropdown-post')
diff --git a/extensions/mentions/js/forum/src/addPostMentionPreviews.js b/extensions/mentions/js/forum/src/addPostMentionPreviews.js
index 3d8c279d5..2177cbc55 100644
--- a/extensions/mentions/js/forum/src/addPostMentionPreviews.js
+++ b/extensions/mentions/js/forum/src/addPostMentionPreviews.js
@@ -7,11 +7,11 @@ export default function addPostMentionPreviews() {
   extend(CommentPost.prototype, 'config', function() {
     const contentHtml = this.props.post.contentHtml();
 
-    if (contentHtml === this.oldPostContentHtml) return;
+    if (contentHtml === this.oldPostContentHtml || this.isEditing()) return;
 
     this.oldPostContentHtml = contentHtml;
 
-    const discussion = this.props.post.discussion();
+    const parentPost = this.props.post;
 
     this.$('.UserMention, .PostMention').each(function() {
       m.route.call(this, this, false, {}, {attrs: {href: this.getAttribute('href')}});
@@ -19,7 +19,7 @@ export default function addPostMentionPreviews() {
 
     this.$('.PostMention').each(function() {
       const $this = $(this);
-      const number = $this.data('number');
+      const id = $this.data('id');
       let timeout;
 
       // Wrap the mention link in a wrapper element so that we can insert a
@@ -29,7 +29,7 @@ export default function addPostMentionPreviews() {
       $this.wrap($wrapper).after($preview);
 
       const getPostElement = () => {
-        return $(`.PostStream-item[data-number="${number}"]`);
+        return $(`.PostStream-item[data-id="${id}"]`);
       };
 
       const showPreview = () => {
@@ -57,18 +57,23 @@ export default function addPostMentionPreviews() {
           };
 
           const showPost = post => {
-            m.render($preview[0], <li>{PostPreview.component({post})}</li>);
+            const discussion = post.discussion();
+
+            m.render($preview[0], [
+              discussion !== parentPost.discussion()
+                ? <li><span className="PostMention-preview-discussion">{discussion.title()}</span></li>
+                : '',
+              <li>{PostPreview.component({post})}</li>
+            ]);
             positionPreview();
           };
 
-          const post = discussion.posts().filter(p => p && p.number() === number)[0];
+          const post = app.store.getById('posts', id);
           if (post) {
             showPost(post);
           } else {
             m.render($preview[0], LoadingIndicator.component());
-            app.store.find('posts', {
-              filter: {discussion: discussion.id(), number}
-            }).then(posts => showPost(posts[0]));
+            app.store.find('posts', id).then(showPost);
             positionPreview();
           }
 
diff --git a/extensions/mentions/js/forum/src/addPostReplyAction.js b/extensions/mentions/js/forum/src/addPostReplyAction.js
index 8be0001d6..d793c4e65 100644
--- a/extensions/mentions/js/forum/src/addPostReplyAction.js
+++ b/extensions/mentions/js/forum/src/addPostReplyAction.js
@@ -10,7 +10,7 @@ export default function() {
     if (post.isHidden() || (app.session.user && !post.discussion().canReply())) return;
 
     function insertMention(component, quote) {
-      const mention = '@' + post.user().username() + '#' + post.number() + ' ';
+      const mention = '@' + post.user().username() + '#' + post.id() + ' ';
 
       // If the composer is empty, then assume we're starting a new reply.
       // In which case we don't want the user to have to confirm if they
diff --git a/extensions/mentions/less/forum/extension.less b/extensions/mentions/less/forum/extension.less
index 5c5c7f521..9e9e743e7 100644
--- a/extensions/mentions/less/forum/extension.less
+++ b/extensions/mentions/less/forum/extension.less
@@ -81,3 +81,7 @@
     border-bottom: 0;
   }
 }
+.PostMention-preview-discussion {
+  padding-top: 0 !important;
+  font-weight: bold !important;
+}
diff --git a/extensions/mentions/src/Listeners/AddPostMentionsFormatter.php b/extensions/mentions/src/Listeners/AddPostMentionsFormatter.php
index 3b3b56b70..e4ac9d8bc 100755
--- a/extensions/mentions/src/Listeners/AddPostMentionsFormatter.php
+++ b/extensions/mentions/src/Listeners/AddPostMentionsFormatter.php
@@ -1,7 +1,6 @@
 <?php namespace Flarum\Mentions\Listeners;
 
 use Flarum\Events\FormatterConfigurator;
-use Flarum\Events\FormatterRenderer;
 use Flarum\Core\Posts\CommentPost;
 
 class AddPostMentionsFormatter
@@ -9,7 +8,6 @@ class AddPostMentionsFormatter
     public function subscribe($events)
     {
         $events->listen(FormatterConfigurator::class, [$this, 'configure']);
-        $events->listen(FormatterRenderer::class, [$this, 'render']);
     }
 
     public function configure(FormatterConfigurator $event)
@@ -21,32 +19,28 @@ class AddPostMentionsFormatter
         $tag = $configurator->tags->add($tagName);
 
         $tag->attributes->add('username');
-        $tag->attributes->add('number');
+        $tag->attributes->add('number')->filterChain->append('#uint');
+        $tag->attributes->add('discussionid')->filterChain->append('#uint');
         $tag->attributes->add('id')->filterChain->append('#uint');
-        $tag->attributes['id']->required = false;
+        $tag->attributes['number']->required = false;
+        $tag->attributes['discussionid']->required = false;
 
-        $tag->template = '<a href="{$DISCUSSION_URL}{@number}" class="PostMention" data-number="{@number}"><xsl:value-of select="@username"/></a>';
-        $tag->filterChain->prepend([static::class, 'addId'])
-            ->addParameterByName('post')
+        $tag->template = '<a href="/d/{@discussionid}/-/{@number}" class="PostMention" data-id="{@id}"><xsl:value-of select="@username"/></a>';
+
+        $tag->filterChain
+            ->prepend([static::class, 'addId'])
             ->setJS('function() { return true; }');
 
-        $configurator->Preg->match('/\B@(?<username>[a-z0-9_-]+)#(?<number>\d+)/i', $tagName);
+        $configurator->Preg->match('/\B@(?<username>[a-z0-9_-]+)#(?<id>\d+)/i', $tagName);
     }
 
-    public function render(FormatterRenderer $event)
+    public static function addId($tag)
     {
-        // TODO: use URL generator
-        $event->renderer->setParameter('DISCUSSION_URL', '/d/' . $event->post->discussion_id . '/-/');
-    }
+        $post = CommentPost::find($tag->getAttribute('id'));
 
-    public static function addId($tag, CommentPost $post)
-    {
-        $id = CommentPost::where('discussion_id', $post->discussion_id)
-            ->where('number', $tag->getAttribute('number'))
-            ->pluck('id');
-
-        if ($id) {
-            $tag->setAttribute('id', $id);
+        if ($post) {
+            $tag->setAttribute('discussionid', (int) $post->discussion_id);
+            $tag->setAttribute('number', (int) $post->number);
 
             return true;
         }