Have Post object track whether it is being used as a catalog OP.

src/General/Index.coffee

@@ -700,7 +700,8 @@ Index =
     if Conf['Index Mode'] is 'catalog'
       nodes = Index.buildCatalogViews threads
       Index.sizeCatalogViews nodes
-    Index.moveComments threads
+    for thread in threads
+      thread.OP.setCatalogOP (Conf['Index Mode'] is 'catalog')
     if Conf['Index Mode'] is 'catalog'
       $.add Index.root, nodes
       if doc.contains Index.root
@@ -715,17 +716,6 @@ Index =
     offset = nodesPerPage * (pageNum - 1)
     Index.sortedThreads[offset ... offset + nodesPerPage]
 
-  moveComments: (threads) ->
-    isCatalog = (Conf['Index Mode'] is 'catalog')
-    for thread in threads
-      node = if isCatalog then thread.catalogView.nodes.root else thread.OP.nodes.post
-      {fileRoot, info, comment} = thread.OP.nodes
-      unless node.contains comment
-        comment.className = if isCatalog then 'comment' else 'postMessage'
-        $.prepend node, fileRoot if fileRoot
-        $.add node, [info, comment]
-    return
-
   buildStructure: (threads) ->
     for thread in threads
       if (file = thread.OP.file) and (thumb = thread.OP.file.thumb) and thumb.dataset.src

src/classes/Post.Clone.coffee

@@ -12,8 +12,7 @@ Post.Clone = class extends Post
     else
       (node) -> node.cloneNode true
     root = cloneNode nodes.root
-    # Handle case where comment has been moved into catalog thread
-    if nodes.comment.parentNode isnt nodes.post
+    if @origin.isCatalogOP
       $.prepend $('.post', root), cloneNode(nodes.fileRoot) if nodes.fileRoot
       $.add $('.post', root), [cloneNode(nodes.info), cloneNode(nodes.comment)]
     Post.Clone.prefix or= 0

src/classes/Post.coffee

@@ -36,8 +36,9 @@ class Post
     @parseQuotes()
     @parseFile()
 
-    @isDead   = false
-    @isHidden = false
+    @isDead      = false
+    @isHidden    = false
+    @isCatalogOP = false
 
     @clones = []
     <% if (readJSON('/.tests_enabled')) { %>
@@ -257,3 +258,12 @@ class Post
     for clone in @clones[index..]
       clone.nodes.root.dataset.clone = index++
     return
+
+  setCatalogOP: (isCatalogOP) ->
+    return if @isCatalogOP is isCatalogOP
+    @isCatalogOP = isCatalogOP
+    node = if isCatalogOP then @thread.catalogView.nodes.root else @nodes.post
+    {fileRoot, info, comment} = @nodes
+    comment.className = if isCatalogOP then 'comment' else 'postMessage'
+    $.prepend node, fileRoot if fileRoot
+    $.add node, [info, comment]