Index: xword/ContentFiltering/Html/CSSUtil.cs
===================================================================
--- xword/ContentFiltering/Html/CSSUtil.cs	(revision 22344)
+++ xword/ContentFiltering/Html/CSSUtil.cs	(working copy)
@@ -106,6 +106,73 @@
         }
 
 
+        /// <summary>
+        /// Groups CSS selectors (CSS classes and ids) with the same properties to minify the generated CSS content.
+        /// </summary>
+        public static Hashtable GroupCSSSelectors(Hashtable existingCSSSelectors)
+        {
+            Hashtable optimizedCSSSelectors = existingCSSSelectors;
 
+            string cssPropsStr;
+            string[] cssProperties;
+            string[] separator = new string[1] { ";" };
+            List<string> cssPropsList = new List<string>();
+
+            //sort css properties from each selector in alphabetic order
+            ICollection cssClassesKeys = optimizedCSSSelectors.Keys;
+
+            //need an extra list in order to alter cssClassesKeys
+            //(can not alter elements while iterate the collection)
+            List<string> xofficeCssClasses = new List<string>();
+            foreach (string key in cssClassesKeys)
+            {
+                xofficeCssClasses.Add(key);
+            }
+
+            foreach (string key in xofficeCssClasses)
+            {
+                cssPropsStr = ((string)optimizedCSSSelectors[key]).Replace('{', ' ').Replace('}', ' ').Trim();
+                cssProperties = cssPropsStr.Split(separator, StringSplitOptions.RemoveEmptyEntries);
+                cssPropsList.Clear();
+                foreach (string property in cssProperties)
+                {
+                    cssPropsList.Add(property.Trim() + ";");
+                }
+                cssPropsList.Sort();
+                cssPropsStr = "{";
+                foreach (string property in cssPropsList)
+                {
+                    cssPropsStr += property;
+                }
+                cssPropsStr += "}";
+                optimizedCSSSelectors[key] = cssPropsStr;
+            }
+
+            //compare CSS selectors and group redundant ones
+            //using an inverted hash of the optimizedCSSSelectors
+            Hashtable invertedHash = new Hashtable(optimizedCSSSelectors.Count);
+            foreach (string key in optimizedCSSSelectors.Keys)
+            {
+                string val = (string)optimizedCSSSelectors[key];
+                string cssClass = "";
+                if (invertedHash.ContainsKey(val))
+                {
+                    cssClass = (string)invertedHash[val];
+                    cssClass += ", ";
+                }
+                cssClass += key;
+                invertedHash[val] = cssClass;
+            }
+            optimizedCSSSelectors.Clear();
+            foreach (string properties in invertedHash.Keys)
+            {
+                string groupedClasses = (string)invertedHash[properties];
+                string props = properties.Replace('{', ' ').Replace('}', ' ').Trim();
+                optimizedCSSSelectors.Add(groupedClasses, props);
+            }
+
+            return optimizedCSSSelectors;
+        }
+
     }
 }
Index: xword/ContentFiltering/Office/Word/Filters/LocalToWebStyleFilter.cs
===================================================================
--- xword/ContentFiltering/Office/Word/Filters/LocalToWebStyleFilter.cs	(revision 22344)
+++ xword/ContentFiltering/Office/Word/Filters/LocalToWebStyleFilter.cs	(working copy)
@@ -6,6 +6,7 @@
 using System.Xml;
 using System.Collections;
 using System.Text.RegularExpressions;
+using ContentFiltering.Html;
 
 namespace ContentFiltering.Office.Word.Filters
 {
@@ -17,7 +18,7 @@
         private int counter = 0;
         private Hashtable cssClasses;
         private ConversionManager manager;
-        
+
         public LocalToWebStyleFilter(ConversionManager manager)
         {
             this.manager = manager;
@@ -28,7 +29,7 @@
         #region IDOMFilter Members
 
         /// <summary>
-        /// Extracts the CSS inline styles, optimizes CSS and adds CSS classes in the head section for current page
+        /// Extracts the inline styles, optimizes CSS and adds CSS classes in the head section for current page
         /// </summary>
         /// <param name="xmlDoc">A reference to a XmlDocument instance.</param>
         public void Filter(ref System.Xml.XmlDocument xmlDoc)
@@ -40,20 +41,25 @@
                 head = xmlDoc.CreateNode(XmlNodeType.Element, "head", xmlDoc.NamespaceURI);
                 body.ParentNode.InsertBefore(head, body);
             }
-            ConvertCSSClassesToInlineStyles(ref head, ref body, ref xmlDoc);
+
+            //step1: inline CSS for existing CSS classes and ids, for better manipulation at step2 and step3
+            CSSUtil.InlineCSS(ref xmlDoc);
+
+            //step2: convert all inlined CSS to CSS classes 
+            //(including, but not limited to, those generated at step1)
             body = ConvertInlineStylesToCssClasses(body, ref xmlDoc);
-            OptimizeCssClasses();
+
+            //step3: optimize CSS by grouping selectors with the same properties
+            cssClasses = CSSUtil.GroupCSSSelectors(cssClasses);
+
             InsertCssClassesInHeader(ref head, ref xmlDoc);
         }
 
         #endregion IDOMFilter Members
 
 
-        private void ConvertCSSClassesToInlineStyles(ref XmlNode head, ref XmlNode body, ref XmlDocument xmlDoc)
-        {
-            //TODO: XOFFICE-125
-        }
 
+
         /// <summary>
         /// Extracts inline styles and replaces them with CSS classes.
         /// </summary>
@@ -168,70 +174,8 @@
             return acceptedProperties.ToString();
         }
 
-        /// <summary>
-        /// Groups CSS classes with the same properties to minify the generated CSS content.
-        /// </summary>
-        private void OptimizeCssClasses()
-        {
-            string cssPropsStr;
-            string[] cssProperties;
-            string[] separator = new string[1] { ";" };
-            List<string> cssPropsList = new List<string>();
 
-            //sort css properties from each class in alphabetic order
-            ICollection cssClassesKeys = cssClasses.Keys;
 
-            //need an extra list in order to alter cssClassesKeys
-            //(can not alter elements while iterate the collection)
-            List<string> xofficeCssClasses = new List<string>();
-            foreach (string key in cssClassesKeys)
-            {
-                xofficeCssClasses.Add(key);
-            }
-
-            foreach (string key in xofficeCssClasses)
-            {
-                cssPropsStr = ((string)cssClasses[key]).Replace('{', ' ').Replace('}', ' ').Trim();
-                cssProperties = cssPropsStr.Split(separator, StringSplitOptions.RemoveEmptyEntries);
-                cssPropsList.Clear();
-                foreach (string property in cssProperties)
-                {
-                    cssPropsList.Add(property.Trim() + ";");
-                }
-                cssPropsList.Sort();
-                cssPropsStr = "{";
-                foreach (string property in cssPropsList)
-                {
-                    cssPropsStr += property;
-                }
-                cssPropsStr += "}";
-                cssClasses[key] = cssPropsStr;
-            }
-
-            //compare CSS classes and group redundant ones
-            //using an inverted hash of the cssClasses
-            Hashtable invertedHash = new Hashtable(cssClasses.Count);
-            foreach (string key in cssClasses.Keys)
-            {
-                string val = (string)cssClasses[key];
-                string cssClass = "";
-                if (invertedHash.ContainsKey(val))
-                {
-                    cssClass = (string)invertedHash[val];
-                    cssClass += ", ";
-                }
-                cssClass += key;
-                invertedHash[val] = cssClass;
-            }
-            cssClasses.Clear();
-            foreach (string properties in invertedHash.Keys)
-            {
-                string groupedClasses = (string)invertedHash[properties];
-                string props = properties.Replace('{', ' ').Replace('}', ' ').Trim();
-                cssClasses.Add(groupedClasses, props);
-            }
-        }
-
         private void InsertCssClassesInHeader(ref XmlNode headNode, ref XmlDocument xmlDoc)
         {
             XmlNode styleNode = xmlDoc.CreateNode(XmlNodeType.Element, "style", xmlDoc.NamespaceURI);
Index: xword/ContentFiltering/Test/Html/CSSUtilTest.cs
===================================================================
--- xword/ContentFiltering/Test/Html/CSSUtilTest.cs	(revision 22344)
+++ xword/ContentFiltering/Test/Html/CSSUtilTest.cs	(working copy)
@@ -6,6 +6,7 @@
 using System.Xml;
 using ContentFiltering.Html;
 using ContentFiltering.Test.Util;
+using System.Collections;
 
 namespace ContentFiltering.Test.Html
 {
@@ -102,7 +103,7 @@
             long stopTicks = DateTime.Now.Ticks;
 
             //inline operation duration, in miliseconds
-            double inlineTimeMS = (1.0*stopTicks - startTicks) / 10000;
+            double inlineTimeMS = (1.0 * stopTicks - startTicks) / 10000;
 
 
             //inline operation should take less than 500 miliseconds
@@ -169,6 +170,65 @@
                 sb.Append("<p id=\"cssID").Append(i).Append("\">Text with CSS ID ").Append(i).Append("</p>");
             }
             return sb.ToString();
-        }        
+        }
+
+        /// <summary>
+        /// Tests the GroupCSSSelectors method.
+        /// </summary>
+        [Test]
+        public void TestGroupCSSSelectors()
+        {
+            Hashtable initialCSSClasses = new Hashtable();
+            Hashtable optimizedCSSClasses = new Hashtable();
+
+            //same initial CSS properties
+            string props1 = "font-family:sans-serif;font-size:100%;color:red;";
+            string props2 = "color:red;font-size:100%;font-family:sans-serif;";
+
+            //the expected properties (ordered alphabetically)
+            string expectedProp = "color:red;font-family:sans-serif;font-size:100%";
+
+            //initial CSS selectors
+            string[] classes1 = { ".xoffice0", ".xoffice1", ".xoffice2", "textarea" };
+            string[] classes2 = { ".xoffice3", ".xoffice4", ".myCssClass", "#one", "p#two" };
+
+            for (int i = 0; i < classes1.Length; i++)
+            {
+                initialCSSClasses.Add(classes1[i], props1);
+            }
+
+            for (int i = 0; i < classes2.Length; i++)
+            {
+                initialCSSClasses.Add(classes2[i], props2);
+            }
+
+
+            optimizedCSSClasses = CSSUtil.GroupCSSSelectors(initialCSSClasses);
+
+            ICollection optimizedKeys = optimizedCSSClasses.Keys;
+
+            //all the selectors should be grouped
+            Assert.IsTrue(optimizedKeys.Count == 1);
+
+            foreach (string key in optimizedKeys)
+            {
+                string val = optimizedCSSClasses[key].ToString();
+
+                //in the new key there must be all initial CSS selectors
+                foreach (string cssClass in classes1)
+                {
+                    Assert.IsTrue(key.IndexOf(cssClass) >= 0);
+                }
+                foreach (string cssClass in classes2)
+                {
+                    Assert.IsTrue(key.IndexOf(cssClass) >= 0);
+                }
+
+                //expected properties are the same, but ordered alphabetically
+                Assert.IsTrue(val.IndexOf(expectedProp) >= 0);
+            }
+
+        }
+
     }
 }