Don't use the IndexBuild event for hiding threads.

src/Filtering/ThreadHiding.coffee

@@ -4,7 +4,7 @@ ThreadHiding =
 
     @db = new DataBoard 'hiddenThreads'
     @syncCatalog()
-    $.on d, 'IndexBuild', @onIndexBuild
+    $.on d, 'IndexRefresh', @onIndexRefresh
     Thread.callbacks.push
       name: 'Thread Hiding'
       cb:   @node
@@ -15,8 +15,8 @@ ThreadHiding =
     return unless Conf['Thread Hiding']
     $.prepend @OP.nodes.root, ThreadHiding.makeButton @, 'hide'
 
-  onIndexBuild: ({detail: nodes}) ->
-    for root, i in nodes by 2
+  onIndexRefresh: ->
+    for root, i in Index.nodes by 2
       thread = Get.threadFromRoot root
       continue unless thread.isHidden
       unless thread.stub

src/General/Index.coffee

@@ -390,8 +390,8 @@ Index =
         nodes = Index.sortedNodes
     $.rmAll Index.root
     Index.buildReplies nodes if Conf['Show Replies'] and Conf['Index Mode'] isnt 'catalog'
-    $.event 'IndexBuild', nodes
     $.add Index.root, nodes
+    $.event 'IndexBuild', nodes
 
   isSearching: false
   clearSearch: ->

src/Monitoring/ThreadWatcher.coffee

@@ -72,9 +72,8 @@ ThreadWatcher =
       else if Conf['Auto Watch Reply']
         ThreadWatcher.add board.threads[threadID]
     onIndexRefresh: ->
-      {db}    = ThreadWatcher
       boardID = g.BOARD.ID
-      for threadID, data of db.data.boards[boardID] when not data.isDead and threadID not of g.BOARD.threads
+      for threadID, data of ThreadWatcher.db.data.boards[boardID] when not data.isDead and threadID not of g.BOARD.threads
         if Conf['Auto Prune']
           ThreadWatcher.db.delete {boardID, threadID}
         else