diff --git a/Debugger/ILSpy.Debugger/Services/Debugger/WindowsDebugger.cs b/Debugger/ILSpy.Debugger/Services/Debugger/WindowsDebugger.cs
index 79cb5dbb8..513e3e0ec 100644
--- a/Debugger/ILSpy.Debugger/Services/Debugger/WindowsDebugger.cs
+++ b/Debugger/ILSpy.Debugger/Services/Debugger/WindowsDebugger.cs
@@ -287,21 +287,22 @@ namespace ILSpy.Debugger.Services
 		
 		// Stepping:
 		
-		SourceCodeMapping GetCurrentCodeMapping()
+		SourceCodeMapping GetCurrentCodeMapping(out bool isMatch)
 		{
+			isMatch = false;
 			if (CurrentLineBookmark.Instance == null)
 				return null;
 			
+			var frame = debuggedProcess.SelectedThread.MostRecentStackFrame;
 			// get the mapped instruction from the current line marker or the next one
-			uint token;
 			return CodeMappingsStorage.GetInstructionByTypeAndLine(
-				CurrentLineBookmark.Instance.Type.FullName,
-				CurrentLineBookmark.Instance.LineNumber, out token);
+				CurrentLineBookmark.Instance.Type.FullName, (uint)frame.MethodInfo.MetadataToken, frame.IP, out isMatch);
 		}
 		
 		StackFrame GetStackFrame()
 		{
-			var map = GetCurrentCodeMapping();
+			bool isMatch;
+			var map = GetCurrentCodeMapping(out isMatch);
 			if (map == null) {
 				CurrentLineBookmark.Remove();
 				Continue();
@@ -309,7 +310,7 @@ namespace ILSpy.Debugger.Services
 			} else {
 				var frame = debuggedProcess.SelectedThread.MostRecentStackFrame;
 				frame.SourceCodeLine = map.SourceCodeLine;
-				frame.ILRanges = map.ToArray();
+				frame.ILRanges = map.ToArray(isMatch);
 				return frame;
 			}
 		}
diff --git a/ICSharpCode.Decompiler/CodeMappings.cs b/ICSharpCode.Decompiler/CodeMappings.cs
index f2c961489..cb27c520f 100644
--- a/ICSharpCode.Decompiler/CodeMappings.cs
+++ b/ICSharpCode.Decompiler/CodeMappings.cs
@@ -42,17 +42,26 @@ namespace ICSharpCode.Decompiler
 		/// <summary>
 		/// Retrieves the array that contains the IL range and the missing gaps between ranges.
 		/// </summary>
-		/// <returns></returns>
-		public int[] ToArray()
+		/// <returns>The array representation of the step aranges.</returns>
+		public int[] ToArray(bool isMatch)
 		{
+			var currentList = new List<ILRange>();
+			
 			// add list for the current source code line
-			var currentList = MemberMapping.MemberCodeMappings
-				.FindAll(m => m.SourceCodeLine == this.SourceCodeLine)
-				.ConvertAll<ILRange>(m => m.ILInstructionOffset);
+			currentList.AddRange(ILRange.OrderAndJoint(MemberMapping.MemberCodeMappings
+			                     .FindAll(m => m.SourceCodeLine == this.SourceCodeLine)
+			                     .ConvertAll<ILRange>(m => m.ILInstructionOffset)));
 			
-			// add inverted
-			currentList.AddRange(MemberMapping.InvertedList);
+			if (!isMatch) {
+				// add inverted
+				currentList.AddRange(MemberMapping.InvertedList);
+			} else {
+				// if the current list contains the last mapping, add also the last gap
+				if (currentList.Count == 1)
+					currentList.Add(MemberMapping.InvertedList.LastOrDefault());
+			}
 			
+			// set the output
 			var resultList = new List<int>();
 			foreach (var element in ILRange.OrderAndJoint(currentList)) {
 				resultList.Add(element.From);
@@ -101,7 +110,7 @@ namespace ICSharpCode.Decompiler
 				if (invertedList == null) {
 					var list = MemberCodeMappings.ConvertAll<ILRange>(
 						s => new ILRange { From = s.ILInstructionOffset.From, To = s.ILInstructionOffset.To });
-					invertedList = ILRange.Invert(list, CodeSize);
+					invertedList = ILRange.OrderAndJoint(ILRange.Invert(list, CodeSize));
 				}
 				return invertedList;
 			}
@@ -201,6 +210,40 @@ namespace ICSharpCode.Decompiler
 			return null;
 		}
 		
+		public static SourceCodeMapping GetInstructionByTypeAndLine(
+			this ConcurrentDictionary<string, List<MemberMapping>> codeMappings,
+			string typeName,
+			uint token,
+			int ilOffset, out bool isMatch)
+		{
+			isMatch = false;
+			
+			if (codeMappings == null)
+				throw new ArgumentNullException("CodeMappings storage must be valid!");
+			
+			if (!codeMappings.ContainsKey(typeName)) {
+				return null;
+			}
+			
+			var methodMappings = codeMappings[typeName];
+			var maping = methodMappings.Find(m => m.MetadataToken == token);
+			// try find an exact match
+			var map = maping.MemberCodeMappings.Find(m => m.ILInstructionOffset.From <= ilOffset && ilOffset < m.ILInstructionOffset.To);
+			
+			if (map == null) {
+				// get the immediate next one
+				map = maping.MemberCodeMappings.Find(m => m.ILInstructionOffset.From >= ilOffset);
+				isMatch = false;
+				if (map == null)
+					map = maping.MemberCodeMappings.LastOrDefault(); // get the last
+				
+				return map;
+			}
+			
+			isMatch = true;
+			return map;
+		}
+		
 		/// <summary>
 		/// Gets the source code and type name from metadata token and offset.
 		/// </summary>
diff --git a/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs b/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
index 5fbd2e385..3608cacc1 100644
--- a/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
+++ b/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
@@ -224,7 +224,10 @@ namespace ICSharpCode.Decompiler.ILAst
 		
 		public static List<ILRange> OrderAndJoint(IEnumerable<ILRange> input)
 		{
-			List<ILRange> ranges = input.OrderBy(r => r.From).ToList();
+			if (input == null)
+				throw new ArgumentNullException("Input is null!");
+						
+			List<ILRange> ranges = input.Where(r => r != null).OrderBy(r => r.From).ToList();
 			for (int i = 0; i < ranges.Count - 1;) {
 				ILRange curr = ranges[i];
 				ILRange next = ranges[i + 1];
@@ -241,6 +244,12 @@ namespace ICSharpCode.Decompiler.ILAst
 		
 		public static IEnumerable<ILRange> Invert(IEnumerable<ILRange> input, int codeSize)
 		{
+			if (input == null)
+				throw new ArgumentNullException("Input is null!");
+			
+			if (codeSize <= 0)
+				throw new ArgumentException("Code size must be grater than 0");
+			
 			var ordered = OrderAndJoint(input);
 			if (ordered.Count == 0) {
 				yield return new ILRange() { From = 0, To = codeSize };