diff --git a/lib/ace/css/editor.css b/lib/ace/css/editor.css
index f0d31f10..ac64e002 100644
--- a/lib/ace/css/editor.css
+++ b/lib/ace/css/editor.css
@@ -237,6 +237,21 @@
     cursor: move;
 }
 
+.ace_gutter_tooltip {
+    background-color: #FFFFD5;
+    border: 1px solid gray;
+    box-shadow: 0 1px 1px rgba(0, 0, 0, 0.4);
+    color: black;
+    display: inline-block;
+    padding: 4px;
+    position: absolute;
+    z-index: 300;
+    box-sizing: border-box;
+    -moz-box-sizing: border-box;
+    -webkit-box-sizing: border-box;
+    cursor: default;
+}
+
 .ace_folding-enabled > .ace_gutter-cell {
     padding-right: 13px;
 }
diff --git a/lib/ace/layer/gutter.js b/lib/ace/layer/gutter.js
index 7c70bbd3..1c6607cb 100644
--- a/lib/ace/layer/gutter.js
+++ b/lib/ace/layer/gutter.js
@@ -103,7 +103,7 @@ var Gutter = function(parentEl) {
     };
 
     this.update = function(config) {
-        var emptyAnno = {className: "", text: []};
+        var emptyAnno = {className: ""};
         var html = [];
         var i = config.firstRow;
         var lastRow = config.lastRow;
@@ -126,7 +126,6 @@ var Gutter = function(parentEl) {
             html.push(
                 "<div class='ace_gutter-cell ",
                 breakpoints[i] || "", decorations[i] || "", annotation.className,
-                "' title='", annotation.text.join("\n"),
                 "' style='height:", this.session.getRowLength(i) * config.lineHeight, "px;'>", 
                 i + 1
             );
diff --git a/lib/ace/mouse/default_gutter_handler.js b/lib/ace/mouse/default_gutter_handler.js
index 0fbadfb7..813f68e9 100644
--- a/lib/ace/mouse/default_gutter_handler.js
+++ b/lib/ace/mouse/default_gutter_handler.js
@@ -39,14 +39,16 @@
 define(function(require, exports, module) {
 "use strict";
 var dom = require("../lib/dom");
+var event = require("../lib/event");
 
 function GutterHandler(mouseHandler) {
     var editor = mouseHandler.editor;
+    var gutter = editor.renderer.$gutterLayer;
 
     mouseHandler.editor.setDefaultHandler("guttermousedown", function(e) {
         if (!editor.isFocused())
             return;
-        var gutterRegion = editor.renderer.$gutterLayer.getRegion(e);
+        var gutterRegion = gutter.getRegion(e);
 
         if (gutterRegion)
             return;
@@ -62,6 +64,98 @@ function GutterHandler(mouseHandler) {
         mouseHandler.captureMouse(e, "selectByLines");
         return e.preventDefault();
     });
+
+
+    var tooltipTimeout, mouseEvent, tooltip, tooltipAnnotation;
+    function createTooltip() {
+        tooltip = dom.createElement("div");
+        tooltip.className = "ace_gutter_tooltip";
+        tooltip.style.maxWidth = "500px";
+        tooltip.style.display = "none";
+        editor.container.appendChild(tooltip);
+    }
+
+    function showTooltip() {
+        if (!tooltip) {
+            createTooltip();
+        }
+        var row = mouseEvent.getDocumentPosition().row;
+        var annotation = gutter.$annotations[row];
+        if (!annotation)
+            return hideTooltip();
+
+        var maxRow = editor.session.getLength();
+        if (row == maxRow) {
+            var screenRow = editor.renderer.pixelToScreenCoordinates(0, mouseEvent.y).row;
+            var pos = mouseEvent.$pos;
+            if (screenRow > editor.session.documentToScreenRow(pos.row, pos.column))
+                return hideTooltip();
+        }
+
+        if (tooltipAnnotation == annotation)
+            return;
+        tooltipAnnotation = annotation.text.join("\n");
+
+        tooltip.style.display = "block";
+        tooltip.innerHTML = tooltipAnnotation;
+        editor.on("mousewheel", hideTooltip);
+
+        moveTooltip(mouseEvent);
+    }
+
+    function hideTooltip() {
+        if (tooltipTimeout)
+            tooltipTimeout = clearTimeout(tooltipTimeout);
+        if (tooltipAnnotation) {
+            tooltip.style.display = "none";
+            tooltipAnnotation = null;
+            editor.removeEventListener("mousewheel", hideTooltip);
+        }
+    }
+
+    function moveTooltip(e) {
+        var rect = editor.renderer.$gutter.getBoundingClientRect();
+        tooltip.style.left = e.x - rect.left + 15 + "px";
+        if (e.y + 3 * editor.renderer.lineHeight + 15 < rect.bottom) {
+            tooltip.style.bottom =  "";
+            tooltip.style.top =  e.y - rect.top + 15 + "px";
+        } else {
+            tooltip.style.top =  "";
+            tooltip.style.bottom = rect.bottom - e.y + 5 + "px";
+        }
+    }
+
+    mouseHandler.editor.setDefaultHandler("guttermousemove", function(e) {
+        var target = e.domEvent.target || e.domEvent.srcElement;
+        if (dom.hasCssClass(target, "ace_fold-widget"))
+            return hideTooltip();
+
+        if (tooltipAnnotation)
+            moveTooltip(e);
+
+        mouseEvent = e;
+        if (tooltipTimeout)
+            return;
+        tooltipTimeout = setTimeout(function() {
+            tooltipTimeout = null;
+            if (mouseEvent)
+                showTooltip();
+            else
+                hideTooltip();
+        }, 50);
+    });
+
+    event.addListener(editor.renderer.$gutter, "mouseout", function(e) {
+        mouseEvent = null;
+        if (!tooltipAnnotation || tooltipTimeout)
+            return;
+
+        tooltipTimeout = setTimeout(function() {
+            tooltipTimeout = null;
+            hideTooltip();
+        }, 50);
+    });
+
 }
 
 exports.GutterHandler = GutterHandler;
diff --git a/lib/ace/mouse/mouse_handler.js b/lib/ace/mouse/mouse_handler.js
index b8e992a3..bf708ee2 100644
--- a/lib/ace/mouse/mouse_handler.js
+++ b/lib/ace/mouse/mouse_handler.js
@@ -69,7 +69,7 @@ var MouseHandler = function(editor) {
     event.addListener(gutterEl, "mousedown", this.onMouseEvent.bind(this, "guttermousedown"));
     event.addListener(gutterEl, "click", this.onMouseEvent.bind(this, "gutterclick"));
     event.addListener(gutterEl, "dblclick", this.onMouseEvent.bind(this, "gutterdblclick"));
-    event.addListener(gutterEl, "mousemove", this.onMouseMove.bind(this, "gutter"));
+    event.addListener(gutterEl, "mousemove", this.onMouseEvent.bind(this, "guttermousemove"));
 };
 
 (function() {