diff --git a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/DefaultHighlightingStrategy.cs b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/DefaultHighlightingStrategy.cs
index 3e8f6e4be9..027b706311 100644
--- a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/DefaultHighlightingStrategy.cs
+++ b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/DefaultHighlightingStrategy.cs
@@ -13,7 +13,7 @@ using System.Windows.Forms;
 
 namespace ICSharpCode.TextEditor.Document
 {
-	public class DefaultHighlightingStrategy : IHighlightingStrategy
+	public class DefaultHighlightingStrategy : IHighlightingStrategyUsingRuleSets
 	{
 		string    name;
 		List<HighlightRuleSet> rules = new List<HighlightRuleSet>();
@@ -174,17 +174,16 @@ namespace ICSharpCode.TextEditor.Document
 		void ResolveExternalReferences()
 		{
 			foreach (HighlightRuleSet ruleSet in Rules) {
+				ruleSet.Highlighter = this;
 				if (ruleSet.Reference != null) {
 					IHighlightingStrategy highlighter = HighlightingManager.Manager.FindHighlighter (ruleSet.Reference);
 					
-					if (highlighter != null) {
-						ruleSet.Highlighter = highlighter;
-					} else {
-						ruleSet.Highlighter = this;
+					if (highlighter == null)
 						throw new HighlightingDefinitionInvalidException("The mode defintion " + ruleSet.Reference + " which is refered from the " + this.Name + " mode definition could not be found");
-					}
-				} else {
-					ruleSet.Highlighter = this;
+					if (highlighter is IHighlightingStrategyUsingRuleSets)
+						ruleSet.Highlighter = (IHighlightingStrategyUsingRuleSets)highlighter;
+					else
+						throw new HighlightingDefinitionInvalidException("The mode defintion " + ruleSet.Reference + " which is refered from the " + this.Name + " mode definition does not implement IHighlightingStrategyUsingRuleSets");
 				}
 			}
 		}
diff --git a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/HighlightRuleSet.cs b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/HighlightRuleSet.cs
index f0a8729005..3459a37d76 100644
--- a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/HighlightRuleSet.cs
+++ b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/HighlightRuleSet.cs
@@ -19,7 +19,6 @@ namespace ICSharpCode.TextEditor.Document
 		ArrayList   spans = new ArrayList();
 		LookupTable prevMarkers;
 		LookupTable nextMarkers;
-		IHighlightingStrategy highlighter = null;
 		char escapeCharacter;
 		
 		bool ignoreCase = false;
@@ -35,14 +34,7 @@ namespace ICSharpCode.TextEditor.Document
 			}
 		}
 		
-		internal IHighlightingStrategy Highlighter {
-			get {
-				return highlighter;
-			}
-			set {
-				highlighter = value;
-			}
-		}
+		internal IHighlightingStrategyUsingRuleSets Highlighter;
 		
 		public LookupTable KeyWords {
 			get {
diff --git a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/IHighlightingStrategy.cs b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/IHighlightingStrategy.cs
index 77888dd88b..fdac3dbb86 100644
--- a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/IHighlightingStrategy.cs
+++ b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/IHighlightingStrategy.cs
@@ -40,26 +40,29 @@ namespace ICSharpCode.TextEditor.Document
 		/// <remarks>
 		/// Gets the color of an Environment element.
 		/// </remarks>
-		HighlightColor   GetColorFor(string name);
+		HighlightColor GetColorFor(string name);
 		
 		/// <remarks>
 		/// Used internally, do not call
 		/// </remarks>
-		HighlightRuleSet GetRuleSet(Span span);
+		void MarkTokens(IDocument document, List<LineSegment> lines);
 		
 		/// <remarks>
 		/// Used internally, do not call
 		/// </remarks>
-		HighlightColor   GetColor(IDocument document, LineSegment keyWord, int index, int length);
-		
+		void MarkTokens(IDocument document);
+	}
+	
+	public interface IHighlightingStrategyUsingRuleSets : IHighlightingStrategy
+	{
 		/// <remarks>
 		/// Used internally, do not call
 		/// </remarks>
-		void MarkTokens(IDocument document, List<LineSegment> lines);
+		HighlightRuleSet GetRuleSet(Span span);
 		
 		/// <remarks>
 		/// Used internally, do not call
 		/// </remarks>
-		void MarkTokens(IDocument document);
+		HighlightColor GetColor(IDocument document, LineSegment keyWord, int index, int length);
 	}
 }