diff --git a/config/vanilla/bootstrap.early.php b/config/vanilla/bootstrap.early.php
index af21e5a..06b250f 100644
--- a/config/vanilla/bootstrap.early.php
+++ b/config/vanilla/bootstrap.early.php
@@ -162,7 +162,13 @@
         // Set count of WatchedCategories for users
         Gdn::sql()->query('update GDN_User u set u.CountWatchedCategories  = (
             select count(c.CategoryID) from GDN_Category c, (select distinct CAST(SUBSTRING_INDEX(um.Name, ".", -1) as UNSIGNED) as CategoryID from GDN_UserMeta  um
-            where um.Name LIKE "Preferences.%" AND UserID = u.UserID and Value = 1) ws where ws.CategoryID = c.CategoryID)');
+            where um.Name LIKE "Preferences.%" AND UserID = u.UserID and Value = 1) ws where ws.CategoryID = c.CategoryID)', 'update');
 
     }
+
+    // FIX: https://github.com/topcoder-platform/forums/issues/479
+    // Re-calculate count of WatchedCategories if WatchedCategories is null
+    Gdn::sql()->query('update GDN_User u set u.CountWatchedCategories  = (
+            select count(c.CategoryID) from GDN_Category c, (select distinct CAST(SUBSTRING_INDEX(um.Name, ".", -1) as UNSIGNED) as CategoryID from GDN_UserMeta  um
+            where um.Name LIKE "Preferences.%" AND UserID = u.UserID and Value = 1) ws where ws.CategoryID = c.CategoryID) where CountWatchedCategories is null', 'update');
 }
\ No newline at end of file
diff --git a/vanilla/applications/vanilla/controllers/class.discussioncontroller.php b/vanilla/applications/vanilla/controllers/class.discussioncontroller.php
index 666047e..177aa68 100644
--- a/vanilla/applications/vanilla/controllers/class.discussioncontroller.php
+++ b/vanilla/applications/vanilla/controllers/class.discussioncontroller.php
@@ -796,7 +796,7 @@ public function deleteComment($commentID = '', $transientKey = '') {
 
             if ($comment && $discussion) {
                 $defaultTarget = discussionUrl($discussion);
-
+                $this->json('DiscussionID', $discussionID);
                 // Make sure comment is this user's or they have Delete permission.
                 if ($comment->InsertUserID != $session->UserID || !c('Vanilla.Comments.AllowSelfDelete')) {
                     $this->categoryPermission($discussion->CategoryID, 'Vanilla.Comments.Delete');
@@ -811,6 +811,12 @@ public function deleteComment($commentID = '', $transientKey = '') {
                 // Delete the comment.
                 if (!$this->CommentModel->deleteID($commentID)) {
                     $this->Form->addError('Failed to delete comment');
+                } else {
+                    // FIX: https://github.com/topcoder-platform/forums/issues/511
+                    // Allow plugins to handle it
+                    $this->EventArguments['DiscussionID'] = $discussionID;
+                    $this->EventArguments['CommentID'] = $commentID;
+                    $this->fireEvent('AfterCommentDeleted');
                 }
             } else {
                 $this->Form->addError('Invalid comment');
diff --git a/vanilla/applications/vanilla/controllers/class.postcontroller.php b/vanilla/applications/vanilla/controllers/class.postcontroller.php
index 3803e90..5ffd811 100644
--- a/vanilla/applications/vanilla/controllers/class.postcontroller.php
+++ b/vanilla/applications/vanilla/controllers/class.postcontroller.php
@@ -395,10 +395,12 @@ public function discussion($categoryUrlCode = '', $announce = '') {
                         $this->EventArguments['Discussion'] = $discussion;
                         $this->fireEvent('AfterDiscussionSave');
 
+                        // FIX: https://github.com/topcoder-platform/forums/issues/511
+                        // if /discussion/{discussionID}/p{Page} is used then view mode is flat
                         if ($this->_DeliveryType == DELIVERY_TYPE_ALL) {
-                            redirectTo(discussionUrl($discussion, 1).'?new=1');
+                            redirectTo(discussionUrl($discussion).'?new=1');
                         } else {
-                            $this->setRedirectTo(discussionUrl($discussion, 1, true).'?new=1');
+                            $this->setRedirectTo(discussionUrl($discussion).'?new=1');
                         }
                     } else {
                         // If this was a draft save, notify the user about the save
diff --git a/vanilla/applications/vanilla/js/discussion.js b/vanilla/applications/vanilla/js/discussion.js
index 1ad3720..fd5ebfd 100755
--- a/vanilla/applications/vanilla/js/discussion.js
+++ b/vanilla/applications/vanilla/js/discussion.js
@@ -135,6 +135,7 @@ jQuery(document).ready(function($) {
                     $('div.Popup,.Overlay').remove();
 
                 var commentID = json.CommentID;
+                var parentCommentID = json.ParentCommentID;
 
                 // Assign the comment id to the form if it was defined
                 if (commentID != null && commentID != '') {
@@ -194,11 +195,19 @@ jQuery(document).ready(function($) {
                             $(json.Data).prependTo('ul.Comments,.DiscussionTable');
                             $('ul.Comments li:first').effect("highlight", {}, "slow");
                         } else {
-                            $(json.Data)
-                                .appendTo('ul.Comments,.DiscussionTable')
-                                .effect("highlight", {}, "slow")
-                                .trigger('contentLoad');
-//                     $('ul.Comments li:last,.DiscussionTable li:last').effect("highlight", {}, "slow");
+                            var viewMode = json['ReplyTo.ViewMode'];
+                            if(viewMode === 'threaded') {
+                                item = $('ul.Comments');
+                                $('ul.Comments li').remove();
+                                $(item).append(json.Data)
+                                  //.effect("highlight", {}, "slow")
+                                  .trigger('contentLoad');
+                            } else {
+                                $(json.Data)
+                                  .appendTo('ul.Comments,.DiscussionTable')
+                                  //.effect("highlight", {}, "slow")
+                                  .trigger('contentLoad');
+                            }
                         }
                     }
                     // Remove any "More" pager links (because it is typically replaced with the latest comment by this function)
@@ -367,7 +376,7 @@ jQuery(document).ready(function($) {
         confirmHeading: gdn.definition('ConfirmDeleteCommentHeading', 'Delete Comment'),
         confirmText: gdn.definition('ConfirmDeleteCommentText', 'Are you sure you want to delete this comment?'),
         followConfirm: false,
-        deliveryType: 'BOOL', // DELIVERY_TYPE_BOOL
+        deliveryType: gdn.urlQueryParam( $('a.DeleteComment').attr('href'), 'deliveryType'), //'VIEW' - threaded, 'BOOL' - flat
         afterConfirm: function(json, sender) {
             var row = $(sender).parents('li.ItemComment');
             if (json.ErrorMessage) {
@@ -378,6 +387,15 @@ jQuery(document).ready(function($) {
                     $(this).remove();
                 });
                 gdn.processTargets(json.Targets);
+
+                var viewMode = json['ReplyTo.ViewMode'];
+                if(viewMode === 'threaded') {
+                    item = $('ul.Comments');
+                    $('ul.Comments li').remove();
+                    $(item).append(json.Data);
+                      //.effect("highlight", {}, "slow");
+                }
+
                 // Let listeners know that the comment was deleted.
                 $(document).trigger('CommentDeleted');
             }
diff --git a/vanilla/applications/vanilla/views/discussion/helper_functions.php b/vanilla/applications/vanilla/views/discussion/helper_functions.php
index c666ba0..8d29f50 100644
--- a/vanilla/applications/vanilla/views/discussion/helper_functions.php
+++ b/vanilla/applications/vanilla/views/discussion/helper_functions.php
@@ -114,7 +114,7 @@ function writeComment($comment, $sender, $session, $currentOffset) {
 
         // FIX: https://github.com/topcoder-platform/forums/issues/488:
         // ViewMode should be set before displaying comment
-        $viewMode = $sender->data('ViewMode');
+        $viewMode = $sender->data('ReplyTo.ViewMode');
         ?>
         <li class="<?php echo $cssClass; ?>" id="<?php echo 'Comment_'.$comment->CommentID; ?>">
             <div class="Comment">
diff --git a/vanilla/applications/vanilla/views/modules/discussionfilter.php b/vanilla/applications/vanilla/views/modules/discussionfilter.php
index 1839692..b08456b 100644
--- a/vanilla/applications/vanilla/views/modules/discussionfilter.php
+++ b/vanilla/applications/vanilla/views/modules/discussionfilter.php
@@ -40,14 +40,28 @@
     <ul role="nav" class="FilterMenu">
         <?php
         $Controller->fireEvent('BeforeDiscussionFilters');
-        //      if (c('Vanilla.Categories.ShowTabs')) {
         if (c('Vanilla.Categories.Use')) {
+            $menuOptions = [];
+
             $CssClass = 'AllCategories';
-            if ((strtolower($Controller->ControllerName) == 'categoriescontroller' && in_array(strtolower($Controller->RequestMethod),['index', 'all']))
-                || strpos(strtolower($Controller->Request->path()) , 'categories') === 0) {
-                $CssClass .= ' Active';
+            $isActive = false;
+            if($Controller instanceof CategoriesController || $Controller instanceof DiscussionController
+                || $Controller instanceof PostController) {
+               $isActive = true;
+            }
+
+            $menuOptions['AllCategories']['Url'] = anchor('Public Forums', '/categories');
+            $menuOptions['AllCategories']['IsActive'] = $isActive;
+            $menuOptions['AllCategories']['CssClass'] = $CssClass;
+
+            $Controller->EventArguments['Menu'] = &$menuOptions;
+            $Controller->fireEvent('BeforeRenderDiscussionFilters');
+            foreach($menuOptions as $key => $value) {
+                if($menuOptions[$key]['IsActive'] === true) {
+                    $menuOptions[$key]['CssClass'] .= ' Active';
+                }
+                echo '<li class="' . $menuOptions[$key]['CssClass'] . '">' . $menuOptions[$key]['Url'] . '</li> ';
             }
-            echo '<li class="'.$CssClass.'">'.anchor('Public Forums', '/categories').'</li> ';
         }
         /*
            <li id="RecentDiscussions" class="Discussions<?php echo strtolower($Controller->ControllerName) == 'discussionscontroller' && strtolower($Controller->RequestMethod) == 'index' && strpos(strtolower($Controller->Request->path()) , 'discussions') === 0? ' Active' : ''; ?>">
diff --git a/vanilla/js/global.js b/vanilla/js/global.js
index 1bd0671..db62050 100644
--- a/vanilla/js/global.js
+++ b/vanilla/js/global.js
@@ -740,6 +740,14 @@ jQuery(document).ready(function($) {
         return urlFormat.replace("{Path}", path);
     };
 
+    // Get query param from url
+    gdn.urlQueryParam = function (url, name) {
+        var results = new RegExp('[\?&]' + name + '=([^&#]*)')
+          .exec(url);
+
+        return (results !== null) ? results[1] || 0 : false;
+    };
+
     // Fill in placeholders.
     if (!gdn.elementSupports('input', 'placeholder')) {
         $('input:text,textarea').not('.NoIE').each(function() {