diff --git a/lib/ace/layer/gutter.js b/lib/ace/layer/gutter.js
index 5a535094..728bb488 100644
--- a/lib/ace/layer/gutter.js
+++ b/lib/ace/layer/gutter.js
@@ -118,9 +118,9 @@ var Gutter = function(parentEl) {
     };
 
     this.update = function(config) {
-        var firstRow = config.firstRow;
-        var lastRow = config.lastRow;
         var session = this.session;
+        var firstRow = config.firstRow;
+        var lastRow = Math.min(config.lastRow + 1, session.getLength() - 1); // needed to compensate
         var fold = session.getNextFoldLine(firstRow);
         var foldStart = fold ? fold.start.row : Infinity;
         var foldWidgets = this.$showFoldWidgets && session.foldWidgets;
diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index f01326dc..477b5ca9 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -894,18 +894,19 @@ var VirtualRenderer = function(container, theme) {
             this.$autosize();
 
         var session = this.session;
+        var size = this.$size;
         
-        var hideScrollbars = this.$size.height <= 2 * this.lineHeight;
+        var hideScrollbars = size.height <= 2 * this.lineHeight;
         var screenLines = this.session.getScreenLength();
         var maxHeight = screenLines * this.lineHeight;
 
         var offset = this.scrollTop % this.lineHeight;
-        var minHeight = this.$size.scrollerHeight + this.lineHeight;
+        var minHeight = size.scrollerHeight + this.lineHeight;
 
         var longestLine = this.$getLongestLine();
         
         var horizScroll = !hideScrollbars && (this.$hScrollBarAlwaysVisible ||
-            this.$size.scrollerWidth - longestLine - 2 * this.$padding < 0);
+            size.scrollerWidth - longestLine - 2 * this.$padding < 0);
 
         var hScrollChanged = this.$horizScroll !== horizScroll;
         if (hScrollChanged) {
@@ -914,15 +915,15 @@ var VirtualRenderer = function(container, theme) {
         }
         
         if (!this.$maxLines && this.$scrollPastEnd) {
-            if (this.scrollTop > maxHeight - this.$size.scrollerHeight)
+            if (this.scrollTop > maxHeight - size.scrollerHeight)
                 maxHeight += Math.min(
-                    (this.$size.scrollerHeight - this.lineHeight) * this.$scrollPastEnd,
-                    this.scrollTop - maxHeight + this.$size.scrollerHeight
+                    (size.scrollerHeight - this.lineHeight) * this.$scrollPastEnd,
+                    this.scrollTop - maxHeight + size.scrollerHeight
                 );
         }
         
         var vScroll = !hideScrollbars && (this.$vScrollBarAlwaysVisible ||
-            this.$size.scrollerHeight - maxHeight < 0);
+            size.scrollerHeight - maxHeight < 0);
         var vScrollChanged = this.$vScroll !== vScroll;
         if (vScrollChanged) {
             this.$vScroll = vScroll;
@@ -930,10 +931,10 @@ var VirtualRenderer = function(container, theme) {
         }
         
         this.session.setScrollTop(Math.max(-this.scrollMargin.top,
-            Math.min(this.scrollTop, maxHeight - this.$size.scrollerHeight + this.scrollMargin.v)));
+            Math.min(this.scrollTop, maxHeight - size.scrollerHeight + this.scrollMargin.v)));
 
         this.session.setScrollLeft(Math.max(-this.scrollMargin.left, Math.min(this.scrollLeft, 
-            longestLine + 2 * this.$padding - this.$size.scrollerWidth + this.scrollMargin.h)));
+            longestLine + 2 * this.$padding - size.scrollerWidth + this.scrollMargin.h)));
 
         var lineCount = Math.ceil(minHeight / this.lineHeight) - 1;
         var firstRow = Math.max(0, Math.round((this.scrollTop - offset) / this.lineHeight));
@@ -955,7 +956,7 @@ var VirtualRenderer = function(container, theme) {
         firstRowHeight = session.getRowLength(firstRow) * lineHeight;
 
         lastRow = Math.min(session.screenToDocumentRow(lastRow, 0), session.getLength() - 1);
-        minHeight = this.$size.scrollerHeight + session.getRowLength(lastRow) * lineHeight +
+        minHeight = size.scrollerHeight + session.getRowLength(lastRow) * lineHeight +
                                                 firstRowHeight;
 
         offset = this.scrollTop - firstRowScreen * lineHeight;
@@ -964,7 +965,7 @@ var VirtualRenderer = function(container, theme) {
         // Horizontal scrollbar visibility may have changed, which changes
         // the client height of the scroller
         if (hScrollChanged || vScrollChanged) {
-            changes = this.$updateCachedSize(true, this.gutterWidth, this.$size.width, this.$size.height);
+            changes = this.$updateCachedSize(true, this.gutterWidth, size.width, size.height);
             this._signal("scrollbarVisibilityChanged");
             if (vScrollChanged)
                 longestLine = this.$getLongestLine();
@@ -981,6 +982,7 @@ var VirtualRenderer = function(container, theme) {
             minHeight : minHeight,
             maxHeight : maxHeight,
             offset : offset,
+            gutterOffset : Math.ceil((offset + size.height - size.scrollerHeight) / lineHeight),
             height : this.$size.scrollerHeight
         };