Merge pull request #924 from edx/gprice/fix-forum-sidebar-overlap

Fix forums nav sidebar overlapping content

common/static/coffee/src/discussion/views/discussion_thread_list_view.coffee

@@ -64,10 +64,8 @@ if Backbone?
 
       sidebar = $(".sidebar")
       if scrollTop > discussionsBodyTop - @sidebar_padding
-        sidebar.addClass('fixed');
-        sidebar.css('top', @sidebar_padding);
+        sidebar.css('top', scrollTop - discussionsBodyTop + @sidebar_padding);
       else
-        sidebar.removeClass('fixed');
         sidebar.css('top', '0');
 
       sidebarWidth = .31 * $(".discussion-body").width();

lms/static/sass/_discussion.scss

@@ -690,14 +690,6 @@ body.discussion {
     border-radius: 3px;
     background: #f6f6f6;
     box-shadow: 0 1px 2px rgba(0, 0, 0, .05);
-
-    &.fixed {
-      @include box-sizing(border-box);
-      position: fixed;
-      top: 0px;
-      width: 32%;
-    }
-
   }
 
   .browse-search {
@@ -1264,10 +1256,6 @@ body.discussion {
     border-radius: 3px;
     background: $white;
     box-shadow: 0 1px 2px rgba(0, 0, 0, .05);
-
-    &.sidebar-fixed {
-      margin-left: 32%;
-    }
   }
 
   .blank-slate {