fixed appearance of loading icon near sort bar

lms/static/coffee/src/discussion/discussion.coffee

@@ -42,9 +42,14 @@ if Backbone?
       DiscussionUtil.safeAjax
         $elem: $elem
         $loading: $elem
+        loadingCallback: ->
+          $(this).parent().append("<span class='discussion-loading'></span>")
+        loadedCallback: ->
+          $(this).parent().children(".discussion-loading").remove()
         url: url
         type: "GET"
         success: (response, textStatus) =>
+          return
           $parent = @$el.parent()
           @$el.replaceWith(response.html)
           $discussion = $parent.find("section.discussion")

lms/static/coffee/src/discussion/utils.coffee

@@ -72,11 +72,17 @@ class @DiscussionUtil
     params["beforeSend"] = ->
       $elem.attr("disabled", "disabled")
       if params["$loading"]
-        params["$loading"].loading()
+        if params["loadingCallback"]?
+          params["loadingCallback"].apply(params["$loading"])
+        else
+          params["$loading"].loading()
     $.ajax(params).always ->
       $elem.removeAttr("disabled")
       if params["$loading"]
-        params["$loading"].loaded()
+        if params["loadedCallback"]?
+          params["loadedCallback"].apply(params["$loading"])
+        else
+          params["$loading"].loaded()
 
   @get: ($elem, url, data, success) ->
     @safeAjax