Make reply hiding button insertion more efficient.

src/Filtering/PostHiding.coffee

@@ -19,7 +19,9 @@ PostHiding =
         Recursive.apply PostHiding.hide, @, data.makeStub, true
         Recursive.add   PostHiding.hide, @, data.makeStub, true
     return unless Conf['Reply Hiding Buttons']
-    $.replace $('.sideArrows', @nodes.root), PostHiding.makeButton @, 'hide'
+    sideArrows = $('.sideArrows', @nodes.root)
+    $.replace sideArrows.firstChild, PostHiding.makeButton @, 'hide'
+    sideArrows.removeAttribute 'class'
 
   menu:
     init: ->

src/General/css/style.css

@@ -1006,6 +1006,9 @@ span.hide-announcement {
 .thread[hidden] + hr {
   display: none;
 }
+:root.reply-hide div.sideArrows {
+  display: none;
+}
 
 /* QR */
 :root.hide-original-post-form #togglePostFormLink,