diff --git a/boards/static/js/thread_update.js b/boards/static/js/thread_update.js
--- a/boards/static/js/thread_update.js
+++ b/boards/static/js/thread_update.js
@@ -273,6 +273,7 @@ function updateOnPost(response, statusTe
 
     if (status === 'ok') {
         resetForm(form);
+        getThreadDiff();
     } else {
         var errors = json.errors;
         for (var i = 0; i < errors.length; i++) {
@@ -322,7 +323,7 @@ function processNewPost(post) {
             beforeSubmit: function(arr, $form, options) {
                 showAsErrors($('form'), gettext('Sending message...'));
             },
-            success: getThreadDiff,
+            success: updateOnPost,
             url: '/api/add_post/' + threadId + '/'
         };