diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index d580c67a..ae16984b 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -244,7 +244,7 @@ var EditSession = function(text, mode) {
                 return mid;
         }
 
-        return low && low -1;
+        return low -1;
     };
 
     this.resetCaches = function() {
@@ -2164,12 +2164,13 @@ var EditSession = function(text, mode) {
 
         var rowCache = this.$screenRowCache;
         var i = this.$getRowCacheIndex(rowCache, screenRow);
-        if (0 < i && i < rowCache.length) {
+        var l = rowCache.length;
+        if (l && i >= 0) {
             var row = rowCache[i];
             var docRow = this.$docRowCache[i];
-            var doCache = screenRow > row || (screenRow == row && i == rowCache.length - 1);
+            var doCache = screenRow > rowCache[l - 1];
         } else {
-            var doCache = i != 0 || !rowCache.length;
+            var doCache = !l;
         }
 
         var maxRow = this.getLength() - 1;
@@ -2189,6 +2190,7 @@ var EditSession = function(text, mode) {
                     foldStart = foldLine ? foldLine.start.row : Infinity;
                 }
             }
+            
             if (doCache) {
                 this.$docRowCache.push(docRow);
                 this.$screenRowCache.push(row);
@@ -2269,12 +2271,13 @@ var EditSession = function(text, mode) {
 
         var rowCache = this.$docRowCache;
         var i = this.$getRowCacheIndex(rowCache, docRow);
-        if (0 < i && i < rowCache.length) {
+        var l = rowCache.length;
+        if (l && i >= 0) {
             var row = rowCache[i];
             var screenRow = this.$screenRowCache[i];
-            var doCache = docRow > row || (docRow == row && i == rowCache.length - 1);
+            var doCache = docRow > rowCache[l - 1];
         } else {
-            var doCache = i != 0 || !rowCache.length;
+            var doCache = !l;
         }
 
         var foldLine = this.getNextFoldLine(row);
diff --git a/lib/ace/edit_session_test.js b/lib/ace/edit_session_test.js
index e89ad57f..07d6b375 100644
--- a/lib/ace/edit_session_test.js
+++ b/lib/ace/edit_session_test.js
@@ -62,6 +62,7 @@ function createFoldTestSession() {
 }
 
 function assertArray(a, b) {
+    assert.equal(a+"", b+"");
     assert.ok(a.length == b.length);
     for (var i = 0; i < a.length; i++) {
         assert.equal(a[i], b[i]);
@@ -980,7 +981,8 @@ module.exports = {
         assertArray(session.$docRowCache, [1,3,4]);
         assertArray(session.$screenRowCache, [1,2,3]);
 
-        session.screenToDocumentPosition(0,0);
+        var pos = session.screenToDocumentPosition(0,0);
+        assert.equal(pos.row, 0);
         assertArray(session.$docRowCache, [1,3,4]);
         assertArray(session.$screenRowCache, [1,2,3]);
         
@@ -991,6 +993,20 @@ module.exports = {
         session.$resetRowCache();
         assertArray(session.$docRowCache, []);
         assertArray(session.$screenRowCache, []);
+        
+        session.screenToDocumentPosition(1,3);
+        assertArray(session.$docRowCache, [1]);
+        assertArray(session.$screenRowCache, [1]);
+       
+        session.screenToDocumentPosition(5,3);
+        assertArray(session.$docRowCache, [1,3,4]);
+        assertArray(session.$screenRowCache, [1,2,3]);
+        
+        session = new EditSession(new Array(30).join("\n"));
+        session.documentToScreenPosition(2,0);
+        session.documentToScreenPosition(2,0);
+        assertArray(session.$docRowCache, [1,2]);
+        assertArray(session.$screenRowCache, [1,2]);
     }
 };
 
diff --git a/lib/ace/scrollbar.js b/lib/ace/scrollbar.js
index b667881c..36619bd5 100644
--- a/lib/ace/scrollbar.js
+++ b/lib/ace/scrollbar.js
@@ -85,7 +85,11 @@ var ScrollBar = function(parent) {
      *
      **/
     this.onScroll = function() {
-        this._emit("scroll", {data: this.element.scrollTop});
+        if (!this.skipEvent) {
+            this.scrollTop = this.element.scrollTop;
+            this._emit("scroll", {data: this.scrollTop});
+        }
+        this.skipEvent = false;
     };
 
     /**
@@ -120,7 +124,7 @@ var ScrollBar = function(parent) {
     };
 
 
-    // TODO: on chrome 17+ for small zoom levels after calling this function
+    // on chrome 17+ for small zoom levels after calling this function
     // this.element.scrollTop != scrollTop which makes page to scroll up.
     /**
      * Sets the scroll top of the scroll bar.
@@ -130,7 +134,10 @@ var ScrollBar = function(parent) {
      *
      **/
     this.setScrollTop = function(scrollTop) {
-        this.element.scrollTop = scrollTop;
+        if (this.scrollTop != scrollTop) {
+            this.skipEvent = true;
+            this.scrollTop = this.element.scrollTop = scrollTop;
+        }
     };
 
 }).call(ScrollBar.prototype);
diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index fa020a79..4661768b 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -96,7 +96,7 @@ var VirtualRenderer = function(container, theme) {
 
     this.setHighlightGutterLine(true);
     this.$gutterLayer = new GutterLayer(this.$gutter);
-    this.$gutterLayer.on("changeGutterWidth", this.onResize.bind(this, true));
+    this.$gutterLayer.on("changeGutterWidth", this.onGutterResize.bind(this));
 
     this.$markerBack = new MarkerLayer(this.content);
 
@@ -239,7 +239,10 @@ var VirtualRenderer = function(container, theme) {
             if (this.$changedLines.lastRow < lastRow)
                 this.$changedLines.lastRow = lastRow;
         }
-
+        
+        if (this.$changedLines.firstRow > this.layerConfig.lastRow ||
+            this.$changedLines.lastRow < this.layerConfig.firstRow)
+            return;
         this.$loop.schedule(this.CHANGE_LINES);
     };
 
@@ -336,6 +339,16 @@ var VirtualRenderer = function(container, theme) {
             delete this.resizing;
     };
 
+    this.onGutterResize = function() {
+        var width = this.$size.width;
+        var gutterWidth = this.showGutter ? this.$gutter.offsetWidth : 0;
+        this.scroller.style.left = gutterWidth + "px";
+        this.$size.scrollerWidth = Math.max(0, width - gutterWidth - this.scrollBar.getWidth());
+
+        if (this.session.getUseWrapMode() && this.adjustWrapLimit())
+            this.$loop.schedule(this.CHANGE_FULL);
+    };
+
     /**
     * 
     * Adjusts the wrap limit, which is the number of characters that can fit within the width of the edit area on screen.