diff --git a/js/src/forum/components/CommentPost.js b/js/src/forum/components/CommentPost.js
index 0bb330485..be5dcda64 100644
--- a/js/src/forum/components/CommentPost.js
+++ b/js/src/forum/components/CommentPost.js
@@ -51,7 +51,7 @@ export default class CommentPost extends Post {
         <ul>{listItems(this.headerItems().toArray())}</ul>
       </header>,
       <div className="Post-body">
-        {this.isEditing() ? <ComposerPostPreview content={() => app.composer.fields.content()} /> : m.trust(this.attrs.post.contentHtml())}
+        {this.isEditing() ? <ComposerPostPreview composer={app.composer} /> : m.trust(this.attrs.post.contentHtml())}
       </div>,
     ]);
   }
diff --git a/js/src/forum/components/ComposerPostPreview.js b/js/src/forum/components/ComposerPostPreview.js
index 13de741c4..390d502b3 100644
--- a/js/src/forum/components/ComposerPostPreview.js
+++ b/js/src/forum/components/ComposerPostPreview.js
@@ -10,7 +10,7 @@ import Component from '../../common/Component';
  *
  * ### Attrs
  *
- * - `content` A callback that retrieves the latest content that should be rendered.
+ * - `composer` The state of the composer controlling this preview.
  */
 export default class ComposerPostPreview extends Component {
   view() {
@@ -24,7 +24,7 @@ export default class ComposerPostPreview extends Component {
     // body with a preview.
     let preview;
     const updatePreview = () => {
-      const content = this.attrs.content();
+      const content = this.attrs.composer.fields.content();
 
       if (preview === content) return;