diff --git a/data/resources/StringResources.resx b/data/resources/StringResources.resx
index c6d41f1639..8737392f68 100644
--- a/data/resources/StringResources.resx
+++ b/data/resources/StringResources.resx
@@ -1729,6 +1729,9 @@ Examples: "120", "MainClass", "Main.cs, 120".</value>
   <data name="Dialog.HighlightingEditor.ColorDlg.Italic" xml:space="preserve">
     <value>Italic</value>
   </data>
+  <data name="Dialog.HighlightingEditor.ColorDlg.Underline" xml:space="preserve">
+    <value>Underlined</value>
+  </data>
   <data name="Dialog.HighlightingEditor.Export" xml:space="preserve">
     <value>Export highlighting colors</value>
   </data>
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CustomizedHighlightingColor.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CustomizedHighlightingColor.cs
index a5df6f78c6..c113ed576c 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CustomizedHighlightingColor.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CustomizedHighlightingColor.cs
@@ -43,6 +43,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		
 		public bool Bold { get; set; }
 		public bool Italic { get; set; }
+		public bool Underline { get; set; }
 		public Color? Foreground { get; set; }
 		public Color? Background { get; set; }
 		
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/CustomizedHighlightingItem.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/CustomizedHighlightingItem.cs
index ce076196b5..e18c5be58a 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/CustomizedHighlightingItem.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/CustomizedHighlightingItem.cs
@@ -66,6 +66,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 		{
 			OnPropertyChanged("Bold");
 			OnPropertyChanged("Italic");
+			OnPropertyChanged("Underline");
 			OnPropertyChanged("Foreground");
 			OnPropertyChanged("UseDefaultForeground");
 			OnPropertyChanged("Background");
@@ -73,7 +74,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			OnPropertyChanged("IsCustomized");
 		}
 		
-		void SetCustomization(bool? bold = null, bool? italic = null,
+		void SetCustomization(bool? bold = null, bool? italic = null, bool? underline = null,
 		                      Color? foreground = null, bool? useDefaultForeground = null,
 		                      Color? background = null, bool? useDefaultBackground = null)
 		{
@@ -82,6 +83,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			newColor.Name = this.Name;
 			newColor.Bold = bold ?? this.Bold;
 			newColor.Italic = italic ?? this.Italic;
+			newColor.Underline = underline ?? this.Underline;
 			
 			if (useDefaultBackground ?? this.UseDefaultBackground)
 				newColor.Background = null;
@@ -99,7 +101,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			else if (customization != null)
 				customizationList.Remove(customization);
 			
-			if (newColor.Bold == original.Bold && newColor.Italic == original.Italic &&
+			if (newColor.Bold == original.Bold && newColor.Italic == original.Italic && newColor.Underline == original.Underline &&
 			    (newColor.Background == null) == original.UseDefaultBackground &&
 			    (newColor.Background == null || newColor.Background == original.Background) &&
 			    (newColor.Foreground == null) == original.UseDefaultForeground &&
@@ -140,6 +142,15 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			}
 		}
 		
+		public bool Underline {
+			get {
+				return (customization != null) ? customization.Underline : original.Underline;
+			}
+			set {
+				SetCustomization(underline: value);
+			}
+		}
+		
 		public Color Foreground {
 			get {
 				return (customization != null) ? (customization.Foreground ?? original.Foreground) : original.Foreground;
@@ -191,7 +202,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 		public void Reset()
 		{
 			original.Reset();
-			SetCustomization(original.Bold, original.Italic, original.Foreground, original.UseDefaultForeground, original.Background, original.UseDefaultBackground);
+			SetCustomization(original.Bold, original.Italic, original.Underline, original.Foreground, original.UseDefaultForeground, original.Background, original.UseDefaultBackground);
 			AllPropertiesChanged();
 		}
 		
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/HighlightingOptions.xaml b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/HighlightingOptions.xaml
index 93508d4370..b78fff3c35 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/HighlightingOptions.xaml
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/HighlightingOptions.xaml
@@ -44,6 +44,8 @@
 				          Content="{core:Localize Dialog.HighlightingEditor.ColorDlg.Bold}"/>
 				<CheckBox IsEnabled="{Binding CanSetFont}" IsChecked="{Binding Italic}"
 				          Content="{core:Localize Dialog.HighlightingEditor.ColorDlg.Italic}"/>
+				<CheckBox IsEnabled="{Binding CanSetFont}" IsChecked="{Binding Underline}"
+				          Content="{core:Localize Dialog.HighlightingEditor.ColorDlg.Underline}"/>
 				<Button Name="resetButton" IsEnabled="{Binding IsCustomized}" HorizontalAlignment="Left"
 				        Click="ResetButtonClick" Style="{x:Static core:GlobalStyles.ButtonStyle}" Margin="0,4"
 				        Content="Reset" />
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/IHighlightingItem.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/IHighlightingItem.cs
index 29d342a800..7852173772 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/IHighlightingItem.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/IHighlightingItem.cs
@@ -43,6 +43,11 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 		/// </summary>
 		bool Italic { get; set; }
 		
+		/// <summary>
+		/// Gets/Sets whether the element uses an underlined font.
+		/// </summary>
+		bool Underline { get; set; }
+		
 		Color Foreground { get; set; }
 		bool UseDefaultForeground { get; set; }
 		Color Background { get; set; }
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/NamedColorHighlightingItem.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/NamedColorHighlightingItem.cs
index c2e158f526..5bc0f4cd7f 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/NamedColorHighlightingItem.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/NamedColorHighlightingItem.cs
@@ -68,6 +68,15 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			}
 		}
 		
+		public bool Underline {
+			get {
+				return color.Underline;
+			}
+			set {
+				throw new NotSupportedException();
+			}
+		}
+		
 		public Color Foreground {
 			get {
 				Color? c = color.Foreground != null ? color.Foreground.GetColor(null) : null;
@@ -161,7 +170,12 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 							marker.ForegroundColor = item.Foreground;
 							marker.FontStyle = item.Italic ? FontStyles.Italic : FontStyles.Normal;
 							marker.FontWeight = item.Bold ? FontWeights.Bold : FontWeights.Normal;
-						});
+							if(item.Underline)
+							{
+								marker.MarkerColor = item.Foreground;
+								marker.MarkerTypes = TextMarkerTypes.NormalUnderline;
+							}
+					});
 				}
 			} else {
 				exampleTextArea.Document.Text = exampleText;
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/SimpleHighlightingItem.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/SimpleHighlightingItem.cs
index 99376357d7..8c165207ec 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/SimpleHighlightingItem.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/SimpleHighlightingItem.cs
@@ -40,6 +40,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 		public string Name { get; private set; }
 		public bool Bold { get; set; }
 		public bool Italic { get; set; }
+		public bool Underline { get; set; }
 		
 		public Color Foreground { get; set; }
 		public bool UseDefaultForeground { get; set; }
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SyntaxHighlighting/CustomizingHighlighter.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SyntaxHighlighting/CustomizingHighlighter.cs
index 0ababb9de6..8f70e0b457 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SyntaxHighlighting/CustomizingHighlighter.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SyntaxHighlighting/CustomizingHighlighter.cs
@@ -267,7 +267,8 @@ namespace ICSharpCode.AvalonEdit.AddIn
 						Background = CreateBrush(customization.Background),
 						Foreground = CreateBrush(customization.Foreground),
 						FontWeight = customization.Bold ? FontWeights.Bold : FontWeights.Normal,
-						FontStyle = customization.Italic ? FontStyles.Italic : FontStyles.Normal
+						FontStyle = customization.Italic ? FontStyles.Italic : FontStyles.Normal,
+						Underline = customization.Underline
 					};
 				}
 			}
diff --git a/src/AddIns/DisplayBindings/HexEditor/Project/Src/View/HexEditOptionsPanel.xaml.cs b/src/AddIns/DisplayBindings/HexEditor/Project/Src/View/HexEditOptionsPanel.xaml.cs
index f1978f6747..8026d1672c 100644
--- a/src/AddIns/DisplayBindings/HexEditor/Project/Src/View/HexEditOptionsPanel.xaml.cs
+++ b/src/AddIns/DisplayBindings/HexEditor/Project/Src/View/HexEditOptionsPanel.xaml.cs
@@ -103,6 +103,8 @@ namespace HexEditor.View
 				preview.FontWeight = FontWeights.Bold;
 			else
 				preview.FontWeight = FontWeights.Normal;
+			if (font.Underline)
+				preview.TextDecorations = TextDecorations.Underline;
 		}
 	}
 }
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightedInlineBuilder.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightedInlineBuilder.cs
index e5f2e24bba..97ada1628a 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightedInlineBuilder.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightedInlineBuilder.cs
@@ -113,7 +113,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 		{
 			if (color == null)
 				throw new ArgumentNullException("color");
-			if (color.Foreground == null && color.Background == null && color.FontStyle == null && color.FontWeight == null) {
+			if (color.Foreground == null && color.Background == null && color.FontStyle == null && color.FontWeight == null && color.Underline == null) {
 				// Optimization: don't split the HighlightingState when we're not changing
 				// any property. For example, the "Punctuation" color in C# is
 				// empty by default.
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColor.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColor.cs
index f8f13182a7..2acaf80a8d 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColor.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColor.cs
@@ -38,6 +38,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 		string name;
 		FontWeight? fontWeight;
 		FontStyle? fontStyle;
+		bool? underline;
 		HighlightingBrush foreground;
 		HighlightingBrush background;
 		bool frozen;
@@ -84,6 +85,20 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 			}
 		}
 		
+		/// <summary>
+      ///  Gets/sets the underline flag. Null if the underline status does not change the font style.
+      /// </summary>
+      public bool? Underline {
+      	get {
+				return underline;
+			}
+			set {
+				if (frozen)
+					throw new InvalidOperationException();
+				underline = value;
+			}
+      }    
+		
 		/// <summary>
 		/// Gets/sets the foreground color applied by the highlighting.
 		/// </summary>
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColorizer.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColorizer.cs
index 68a625745e..10527b3843 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColorizer.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/HighlightingColorizer.cs
@@ -18,6 +18,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Windows;
 using System.Windows.Media;
 using ICSharpCode.AvalonEdit.Document;
 using ICSharpCode.AvalonEdit.Rendering;
@@ -231,7 +232,8 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 			if (color == null)
 				return true;
 			return color.Background == null && color.Foreground == null
-				&& color.FontStyle == null && color.FontWeight == null;
+				&& color.FontStyle == null && color.FontWeight == null
+				&& color.Underline == null;
 		}
 		
 		/// <summary>
@@ -254,7 +256,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 				if (b != null)
 					element.BackgroundBrush = b;
 			}
-			if (color.FontStyle != null || color.FontWeight != null) {
+			if (color.FontStyle != null || color.FontWeight != null || color.Underline != null) {
 				Typeface tf = element.TextRunProperties.Typeface;
 				element.TextRunProperties.SetTypeface(new Typeface(
 					tf.FontFamily,
@@ -263,6 +265,8 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 					tf.Stretch
 				));
 			}
+			if(color.Underline ?? false)
+               element.TextRunProperties.SetTextDecorations(TextDecorations.Underline);           
 		}
 		
 		/// <summary>
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/V2Loader.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/V2Loader.cs
index 7a239d8196..70b2539dc8 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/V2Loader.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/V2Loader.cs
@@ -297,6 +297,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting.Xshd
 			color.Background = ParseColor(position, reader.GetAttribute("background"));
 			color.FontWeight = ParseFontWeight(reader.GetAttribute("fontWeight"));
 			color.FontStyle = ParseFontStyle(reader.GetAttribute("fontStyle"));
+			color.Underline = reader.GetAttribute("underline") == "true";
 			return color;
 		}
 		
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XmlHighlightingDefinition.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XmlHighlightingDefinition.cs
index 62128c81fa..9743277ba8 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XmlHighlightingDefinition.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XmlHighlightingDefinition.cs
@@ -204,6 +204,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting.Xshd
 				c.Name = color.Name;
 				c.Foreground = color.Foreground;
 				c.Background = color.Background;
+				c.Underline = color.Underline;
 				c.FontStyle = color.FontStyle;
 				c.FontWeight = color.FontWeight;
 				return c;
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XshdColor.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XshdColor.cs
index 3812a57e71..7ec202641e 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XshdColor.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Highlighting/Xshd/XshdColor.cs
@@ -49,6 +49,11 @@ namespace ICSharpCode.AvalonEdit.Highlighting.Xshd
 		/// </summary>
 		public FontWeight? FontWeight { get; set; }
 		
+		/// <summary>
+		/// Gets/sets the underline flag
+		/// </summary>
+		public bool Underline { get; set; }
+		
 		/// <summary>
 		/// Gets/sets the font style.
 		/// </summary>
@@ -81,6 +86,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting.Xshd
 			if (info.GetBoolean("HasStyle"))
 				this.FontStyle = (FontStyle?)new FontStyleConverter().ConvertFromInvariantString(info.GetString("Style"));
 			this.ExampleText = info.GetString("ExampleText");
+			this.Underline = info.GetBoolean("Underline");
 		}
 		
 		/// <summary>
@@ -99,6 +105,8 @@ namespace ICSharpCode.AvalonEdit.Highlighting.Xshd
 			info.AddValue("Foreground", this.Foreground);
 			info.AddValue("Background", this.Background);
 			info.AddValue("HasWeight", this.FontWeight.HasValue);
+			if (this.Underline)
+            info.AddValue("Underline", this.Underline);			
 			if (this.FontWeight.HasValue)
 				info.AddValue("Weight", this.FontWeight.Value.ToOpenTypeWeight());
 			info.AddValue("HasStyle", this.FontStyle.HasValue);