diff --git a/app/assets/javascripts/discourse/lib/Markdown.Editor.js b/app/assets/javascripts/discourse/lib/Markdown.Editor.js
index c011a0ca6..1e3fec006 100644
--- a/app/assets/javascripts/discourse/lib/Markdown.Editor.js
+++ b/app/assets/javascripts/discourse/lib/Markdown.Editor.js
@@ -861,6 +861,7 @@
         var oldInputText;
         var maxDelay = 3000;
         var startType = "delayed"; // The other legal value is "manual"
+        var scrollSyncOn = !!panels.previewScroller;
 
         var paneContentHeight = function(pane) {
           var $pane = $(pane);
@@ -869,11 +870,10 @@
           return pane.scrollHeight - paneVerticalPadding;
         };
 
-        var prevScrollPosition = $(panels.input).scrollTop();
-        var caretMarkerPosition = 0;
-        var markerPositions;
-        if (panels.previewScroller) {
-          markerPositions = {
+        if (scrollSyncOn) {
+          var prevScrollPosition = $(panels.input).scrollTop();
+          var caretMarkerPosition = 0;
+          var markerPositions = {
             scroller: [0, paneContentHeight(panels.previewScroller)],
             preview: [0, paneContentHeight(panels.preview)]
           };
@@ -1020,21 +1020,28 @@
 
             var prevTime = new Date().getTime();
 
-            var caretPosition = getCaretPosition();
-            text = text.slice(0, caretPosition) + '~~caret~~' + text.slice(caretPosition);
-            text = text.replace(/(\n|\r|\r\n)(\n|\r|\r\n)+/g, "$&~~marker~~$1$1");
+            var previewText;
+            var previewScrollerText;
 
-            previewText = converter.makeHtml(text.replace('~~caret~~', ''))
-              .replace(/<p>~~marker~~<\/p>/g, '<span class="marker"></span>')
-              .replace(/~~marker~~/g, '<span class="marker"></span>');
+            if (scrollSyncOn) {
+              var caretPosition = getCaretPosition();
+              text = text.slice(0, caretPosition) + '~~caret~~' + text.slice(caretPosition);
+              text = text.replace(/(\n|\r|\r\n)(\n|\r|\r\n)+/g, "$&~~marker~~$1$1");
 
-            previewScrollerText = text
-              .replace(/&/g, '&amp;')
-              .replace(/</g, '&lt;')
-              .replace(/>/g, '&gt;')
-              .replace(/(\n|\r|\r\n)/g, '<br>')
-              .replace('~~caret~~', '<span class="caret"></span>')
-              .replace(/~~marker~~<br><br>/g, '<span class="marker"></span>');
+              previewText = converter.makeHtml(text.replace('~~caret~~', ''))
+                .replace(/<p>~~marker~~<\/p>/g, '<span class="marker"></span>')
+                .replace(/~~marker~~/g, '<span class="marker"></span>');
+
+              previewScrollerText = text
+                .replace(/&/g, '&amp;')
+                .replace(/</g, '&lt;')
+                .replace(/>/g, '&gt;')
+                .replace(/(\n|\r|\r\n)/g, '<br>')
+                .replace('~~caret~~', '<span class="caret"></span>')
+                .replace(/~~marker~~<br><br>/g, '<span class="marker"></span>');
+            } else {
+              previewText = converter.makeHtml(text);
+            }
 
             // Calculate the processing time of the HTML creation.
             // It's used as the delay time in the event listener.
@@ -1043,7 +1050,7 @@
 
             Ember.run(function() {
               pushPreviewHtml(previewText, previewScrollerText);
-              if (panels.previewScroller) {
+              if (scrollSyncOn) {
                 cacheMarkerPositions();
                 cacheCaretMarkerPosition();
                 syncScroll(true);
@@ -1154,14 +1161,14 @@
             };
 
             ieSafeSet(panels.preview, previewText);
-            if (panels.previewScroller) {
+            if (scrollSyncOn) {
               ieSafeSet(panels.previewScroller, previewScrollerText);
             }
         }
 
         var nonSuckyBrowserPreviewSet = function (previewText, previewScrollerText) {
             panels.preview.innerHTML = previewText;
-            if (panels.previewScroller) {
+            if (scrollSyncOn) {
               panels.previewScroller.innerHTML = previewScrollerText;
             }
         }
@@ -1213,7 +1220,7 @@
             // TODO: make option to disable. We don't need this in discourse
             // setupEvents(panels.input, applyTimeout);
 
-            if (panels.previewScroller) {
+            if (scrollSyncOn) {
               setupScrollSync();
             }