diff --git a/lib/ace/document.js b/lib/ace/document.js
index 67b16daa..d16c769e 100644
--- a/lib/ace/document.js
+++ b/lib/ace/document.js
@@ -772,10 +772,14 @@ var Document = function(text, mode) {
     this.$useWrapMode = false;
     this.setUseWrapMode = function(useWrapMode) {
         var _self = this;
+
         function computeWrapData(e) {
             var lines = _self.lines, wrapData = _self.$wrapData;
             var wrapLimit = _self.$wrapLimit;
 
+            // Remove lines that are no longer there.
+            wrapData.splice(lines.length, wrapData.length - lines.length);
+
             if (!e.data.lastRow) {
                 e.data.lastRow = _self.lines.length - 1;
             }
@@ -857,6 +861,21 @@ var Document = function(text, mode) {
         return docColumn;
     };
 
+    this.screenToDocumentRow = function(row) {
+        if (!this.$useWrapMode) {
+            return row;
+        }
+
+        var wrapData = this.$wrapData, linesCount = this.lines.length;
+        var docRow = 0;
+        while (docRow < linesCount && row >= wrapData[docRow].length + 1) {
+            row -= wrapData[docRow].length + 1;
+            docRow ++;
+        }
+
+        return docRow;
+    };
+
     this.screenToDocumentPosition = function(row, column) {
         if (!this.$useWrapMode) {
             return {
@@ -903,7 +922,7 @@ var Document = function(text, mode) {
         return screenColumn;
     };
 
-    this.documentToScreenPosition = function(row, column) {
+    this.documentToScreenRow = function(row) {
         if (!this.$useWrapMode) {
             return {
                 row: row,
@@ -919,19 +938,27 @@ var Document = function(text, mode) {
             for (row = 0; row < wrapData.length; row ++) {
                 screenRow += wrapData[row].length + 1;
             }
-            return {
-                row: screenRow,
-                column: 0
-            }
+            return screenRow;
         }
 
         for (var i = 0; i < row; i++) {
             screenRow += wrapData[i].length + 1;
         }
 
+        return screenRow;
+    }
+
+    this.documentToScreenPosition = function(row, column) {
+        if (!this.$useWrapMode) {
+            return {
+                row: row,
+                column: this.documentToScreenColumn(row, column)
+            }
+        }
+        var screenRow = this.documentToScreenRow(row);
         var screenColumn = column;
-        var wrapRowData = wrapData[row];
-        for (var split = 0; split < wrapRowData.length; split++) {
+        var wrapRowData = this.$wrapData[row];
+        for (var split = 0; wrapRowData && split < wrapRowData.length; split++) {
             if (column > wrapRowData[split]) {
                 screenColumn = column - wrapRowData[split];
                 screenRow ++;
@@ -946,6 +973,18 @@ var Document = function(text, mode) {
         };
     };
 
+    this.getScreenLength = function() {
+        if (!this.$useWrapMode) {
+            return this.getLength();
+        }
+
+        var screenRows = 0;
+        for (var row = 0; row < this.$wrapData.length; row++) {
+            screenRows += this.$wrapData[row].length + 1;
+        }
+        return screenRows;
+    }
+
 }).call(Document.prototype)
 
 exports.Document = Document;
diff --git a/lib/ace/layer/cursor.js b/lib/ace/layer/cursor.js
index 8fcbb1c1..f614ca89 100644
--- a/lib/ace/layer/cursor.js
+++ b/lib/ace/layer/cursor.js
@@ -100,7 +100,7 @@ var Cursor = function(parentEl) {
         }, 1000);
     };
 
-    this.getPixelPosition = function() {
+    this.getPixelPosition = function(onScreen) {
         if (!this.config || !this.position) {
             return {
                 left : 0,
@@ -111,7 +111,8 @@ var Cursor = function(parentEl) {
         var pos = this.doc.documentToScreenPosition(this.position.row,
                                                     this.position.column);
         var cursorLeft = Math.round(pos.column * this.config.characterWidth);
-        var cursorTop = pos.row * this.config.lineHeight;
+        var cursorTop = (pos.row - (onScreen ? this.config.firstRowScreen : 0)) *
+            this.config.lineHeight;
 
         return {
             left : cursorLeft,
@@ -125,7 +126,7 @@ var Cursor = function(parentEl) {
 
         this.config = config;
 
-        this.pixelPos = this.getPixelPosition();
+        this.pixelPos = this.getPixelPosition(true);
 
         this.cursor.style.left = this.pixelPos.left + "px";
         this.cursor.style.top =  this.pixelPos.top + "px";
diff --git a/lib/ace/layer/marker.js b/lib/ace/layer/marker.js
index 517f1775..2ef477ab 100644
--- a/lib/ace/layer/marker.js
+++ b/lib/ace/layer/marker.js
@@ -102,6 +102,10 @@ var Marker = function(parentEl) {
         this.element.innerHTML = html.join("");
     };
 
+    this.$getTop = function(row, layerConfig) {
+        return (row - layerConfig.firstRowScreen) * layerConfig.lineHeight;
+    };
+
     this.drawTextMarker = function(stringBuilder, range, clazz, layerConfig) {
         // selection start
         var row = range.start.row;
@@ -125,7 +129,7 @@ var Marker = function(parentEl) {
         // from selection start to the end of the line
         var height = layerConfig.lineHeight;
         var width = Math.round(layerConfig.width - (range.start.column * layerConfig.characterWidth));
-        var top = (range.start.row - layerConfig.firstRow) * layerConfig.lineHeight;
+        var top = this.$getTop(range.start.row, layerConfig);
         var left = Math.round(range.start.column * layerConfig.characterWidth);
 
         stringBuilder.push(
@@ -137,7 +141,7 @@ var Marker = function(parentEl) {
         );
 
         // from start of the last line to the selection end
-        var top = (range.end.row - layerConfig.firstRow) * layerConfig.lineHeight;
+        var top = this.$getTop(range.start.end, layerConfig);
         var width = Math.round(range.end.column * layerConfig.characterWidth);
 
         stringBuilder.push(
@@ -151,7 +155,7 @@ var Marker = function(parentEl) {
         var height = (range.end.row - range.start.row - 1) * layerConfig.lineHeight;
         if (height < 0)
             return;
-        var top = (range.start.row + 1 - layerConfig.firstRow) * layerConfig.lineHeight;
+        var top = this.$getTop(range.start.row + 1, layerConfig);
 
         stringBuilder.push(
             "<div class='", clazz, "' style='",
@@ -164,7 +168,7 @@ var Marker = function(parentEl) {
     this.drawSingleLineMarker = function(stringBuilder, range, clazz, layerConfig) {
         var height = layerConfig.lineHeight;
         var width = Math.round((range.end.column - range.start.column) * layerConfig.characterWidth);
-        var top = (range.start.row - layerConfig.firstRow) * layerConfig.lineHeight;
+        var top = this.$getTop(range.start.row, layerConfig);
         var left = Math.round(range.start.column * layerConfig.characterWidth);
 
         stringBuilder.push(
diff --git a/lib/ace/layer/text.js b/lib/ace/layer/text.js
index 5c26a4f2..c7135ed0 100644
--- a/lib/ace/layer/text.js
+++ b/lib/ace/layer/text.js
@@ -96,15 +96,15 @@ var Text = function(parentEl) {
         if (!this.$measureNode) {
 	        var measureNode = this.$measureNode = document.createElement("div");
 	        var style = measureNode.style;
-	
+
 	        style.width = style.height = "auto";
 	        style.left = style.top = "-1000px";
-	
+
 	        style.visibility = "hidden";
 	        style.position = "absolute";
 	        style.overflow = "visible";
 	        style.whiteSpace = "nowrap";
-	
+
 	        // in FF 3.6 monospace fonts can have a fixed sub pixel width.
 	        // that's why we have to measure many characters
 	        // Note: characterWidth can be a float!
@@ -151,6 +151,12 @@ var Text = function(parentEl) {
     this.updateLines = function(config, firstRow, lastRow) {
         console.log("layer.text.updateLines", firstRow, lastRow);
         this.$computeTabString();
+        // Due to wrap line changes there can be new lines if e.g.
+        // the line to updated wrapped in the meantime.
+        if (this.config.lastRow != config.lastRow ||
+            this.config.firstRow != config.firstRow) {
+            this.scrollLines(config);
+        }
         this.config = config;
 
         var first = Math.max(firstRow, config.firstRow);
@@ -273,6 +279,7 @@ var Text = function(parentEl) {
     };
 
     this.$renderLine = function(stringBuilder, row, tokens) {
+        console.log("layer.text.renderLine", row);
 //        if (this.$showInvisibles) {
 //            var self = this;
 //            var spaceRe = /[\v\f \u00a0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000]+/g;
diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index ab66a443..e405b6f8 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -326,7 +326,7 @@ var VirtualRenderer = function(container, theme) {
     };
 
     this.$updateScrollBar = function() {
-        this.scrollBar.setInnerHeight(this.doc.getLength() * this.lineHeight);
+        this.scrollBar.setInnerHeight(this.doc.getScreenLength() * this.lineHeight);
         this.scrollBar.setScrollTop(this.scrollTop);
     };
 
@@ -399,12 +399,23 @@ var VirtualRenderer = function(container, theme) {
 
         var lineCount = Math.ceil(minHeight / this.lineHeight);
         var firstRow = Math.max(0, Math.round((this.scrollTop - offset) / this.lineHeight));
-        var lastRow = Math.max(0, Math.min(this.lines.length, firstRow + lineCount) - 1);
+        //var lastRow = Math.max(0, Math.min(this.lines.length, firstRow + lineCount) - 1);
+        var lastRow = firstRow + lineCount - 1;
+
+        // Add support for wrapped lines.
+        var lineHeight = { lineHeight: this.lineHeight };
+        firstRow = this.doc.screenToDocumentRow(firstRow);
+        var firstRowScreen = this.doc.documentToScreenRow(firstRow);
+        lastRow = Math.min(this.doc.screenToDocumentRow(lastRow), this.doc.lines.length - 1);
+        offset = this.scrollTop % this.doc.getRowHeight(lineHeight, firstRow);
+        console.log("renderer.computeLayerConfig", firstRow, lastRow);
+
 
         var layerConfig = this.layerConfig = {
             width : longestLine,
             padding : this.$padding,
             firstRow : firstRow,
+            firstRowScreen: firstRowScreen,
             lastRow : lastRow,
             lineHeight : this.lineHeight,
             characterWidth : this.characterWidth,
@@ -542,7 +553,7 @@ var VirtualRenderer = function(container, theme) {
     };
 
     this.scrollToY = function(scrollTop) {
-        var maxHeight = this.lines.length * this.lineHeight - this.$size.scrollerHeight;
+        var maxHeight = this.doc.getScreenLength() * this.lineHeight - this.$size.scrollerHeight;
         var scrollTop = Math.max(0, Math.min(maxHeight, scrollTop));
 
         if (this.scrollTop !== scrollTop) {