diff --git a/app/views/request_for_comments/show.html.erb b/app/views/request_for_comments/show.html.erb
index 470dcf8f..92892b04 100644
--- a/app/views/request_for_comments/show.html.erb
+++ b/app/views/request_for_comments/show.html.erb
@@ -137,6 +137,7 @@ also, all settings from the rails model needed for the editor configuration in t
     currentEditor.getSession().setMode($(editor).data('mode'));
     currentEditor.getSession().setOption("useWorker", false);
 
+    currentEditor.annotationsByLine = {};
     setAnnotations(currentEditor, $(editor).data('file-id'));
     currentEditor.on("guttermousedown", handleSidebarClick);
   });
@@ -147,73 +148,90 @@ also, all settings from the rails model needed for the editor configuration in t
   }
 
   function preprocess(commentText) {
-      // sanitize comments to deal with XSS attacks:
-      commentText = $('div.sanitizer').text(commentText).html();
-      // display original line breaks:
-      return commentText.replace(/\n/g, '<br>');
+    // sanitize comments to deal with XSS attacks:
+    commentText = $('div.sanitizer').text(commentText).html();
+    // display original line breaks:
+    return commentText.replace(/\n/g, '<br>');
+  }
+
+  function clusterComments(comments) {
+    var clusters = {};
+    // comments need to be sorted to cluster them per line
+    comments.sort(function (a, b) {
+      return a.row - b.row;
+    });
+    while (comments.length > 0) {
+      // new cluster of comments
+      var cluster = [];
+      var clusterRow = comments[0].row;
+      // now collect all comments on this line
+      while (comments.length > 0 && comments[0].row === clusterRow) {
+          cluster.push(comments.shift());
+      }
+      // sort the comments by creation date
+      cluster = cluster.sort(function (a, b) {
+        return a.id - b.id;
+      });
+      clusters[clusterRow] = cluster;
+    }
+    return clusters;
+  }
+
+  function generateCommentHtmlContent(comments) {
+    var htmlContent = '';
+    comments.forEach(function(comment, index) {
+      if (index !== 0) {
+        htmlContent += '<div class="popover-divider"></div>'
+      }
+      htmlContent += '<p class="comment">';
+      htmlContent += '<div class="popover-header">' +
+        '<div class="popover-username">' + preprocess(comment.username) + '</div>' +
+        '<div class="popover-date">' + comment.date + '</div>';
+      if (comment.updated) {
+        htmlContent += '<div class="popover-updated">' +
+          '<i class="fa fa-pencil" aria-hidden="true"></i>' +
+          '<%= t('request_for_comments.comment_edited') %>' +
+          '</div>'
+      }
+      htmlContent += '</div>';
+      htmlContent += '<div class="popover-comment">' + preprocess(comment.text) + '</div>';
+      htmlContent += '</p>';
+    });
+    return htmlContent;
+  }
+
+  function buildPopover(fileid, line, htmlContent) {
+    // attach the popover to the ace sidebar (where the comment icon is displayed)
+    var icon = $('*[data-file-id="' + fileid + '"]')          // the editor for this file
+      .find('.ace_gutter > .ace_gutter-layer')                // the sidebar
+      .find('div:nth-child(' + (parseInt(line) + 1) + ')');   // the correct line
+    icon.popover({
+      content: htmlContent,
+      html: true, // necessary to style comments. XSS is not possible due to comment pre-processing (sanitizing)
+      trigger: 'hover',
+      container: 'body'
+    });
   }
 
   function setAnnotations(editor, fileid) {
     var session = editor.getSession();
 
     var jqrequest = $.ajax({
-        dataType: 'json',
-        method: 'GET',
-        url: '/comments',
-        data: {
-          file_id: fileid
-        }
+      dataType: 'json',
+      method: 'GET',
+      url: '/comments',
+      data: {
+        file_id: fileid
+      }
     });
 
     jqrequest.done(function(response){
-      // comments need to be sorted to cluster them per line
-      var comments = response.slice().sort(function (a, b) {
-          return a.row - b.row;
-      });
-      while (comments.length > 0) {
-        // new cluster of comments
-        var cluster = [];
-        var clusterRow = comments[0].row;
-        // now collect all comments on this line
-        while (comments.length > 0 && comments[0].row === clusterRow) {
-          cluster.push(comments.shift());
+      editor.annotationsByLine = clusterComments(response.slice());
+      for (var line in editor.annotationsByLine) {
+        if (editor.annotationsByLine.hasOwnProperty(line)) {
+          var htmlContent = generateCommentHtmlContent(editor.annotationsByLine[line]);
+          buildPopover(fileid, line, htmlContent);
         }
-        // sort the comments by creation date
-        cluster = cluster.sort(function (a, b) {
-            return a.id - b.id;
-        });
-
-        // build the markup for the current line's popover
-        var popupContent = '';
-        cluster.forEach(function(comment, index) {
-            if (index !== 0) {
-                popupContent += '<div class="popover-divider"></div>'
-            }
-            popupContent += '<p class="comment">';
-            popupContent += '<div class="popover-header">' +
-                '<div class="popover-username">' + preprocess(comment.username) + '</div>' +
-                '<div class="popover-date">' + comment.date + '</div>';
-            if (comment.updated) {
-                popupContent += '<div class="popover-updated">' +
-                    '<i class="fa fa-pencil" aria-hidden="true"></i>' +
-                    '<%= t('request_for_comments.comment_edited') %>' +
-                    '</div>'
-            }
-            popupContent += '</div>';
-            popupContent += '<div class="popover-comment">' + preprocess(comment.text) + '</div>';
-            popupContent += '</p>';
-        });
-
-        // attach the popover to the ace sidebar (where the comment icon is displayed)
-        var icon = $('*[data-file-id="' + fileid + '"]')          // the editor for this file
-                .find('.ace_gutter > .ace_gutter-layer')          // the sidebar
-                .find('div:nth-child(' + (clusterRow + 1) + ')'); // the correct line
-        icon.popover({
-          content: popupContent,
-          html: true, // necessary to style comments. XSS is not possible due to comment pre-processing (sanitizing)
-          trigger: 'hover',
-          container: 'body'
-        });
       }
 
       $.each(response, function(index, comment) {