diff --git a/src/AddIns/DisplayBindings/ILSpyAddIn/ViewContent/DecompiledViewContent.cs b/src/AddIns/DisplayBindings/ILSpyAddIn/ViewContent/DecompiledViewContent.cs
index 705cc0b8ab..40cf4f7b4b 100644
--- a/src/AddIns/DisplayBindings/ILSpyAddIn/ViewContent/DecompiledViewContent.cs
+++ b/src/AddIns/DisplayBindings/ILSpyAddIn/ViewContent/DecompiledViewContent.cs
@@ -233,6 +233,11 @@ namespace ICSharpCode.ILSpyAddIn
 				
 				debugInformation.CodeMappings[token].GetInstructionByTokenAndOffset(token, ilOffset, out member, out line);
 				
+				// HACK : if the codemappings are not built
+				if (line == 0) {
+					DebuggerService.CurrentDebugger.StepOver();
+					return;
+				}
 				// update bookmark & marker
 				codeView.UnfoldAndScroll(line);
 				CurrentLineBookmark.SetPosition(this, line, 0, line, 0);
diff --git a/src/Main/Base/Project/Src/Services/Debugger/CurrentLineBookmark.cs b/src/Main/Base/Project/Src/Services/Debugger/CurrentLineBookmark.cs
index 921c33231d..9a80788f46 100644
--- a/src/Main/Base/Project/Src/Services/Debugger/CurrentLineBookmark.cs
+++ b/src/Main/Base/Project/Src/Services/Debugger/CurrentLineBookmark.cs
@@ -14,6 +14,7 @@ namespace ICSharpCode.SharpDevelop.Debugging
 {
 	public class CurrentLineBookmark : SDMarkerBookmark
 	{
+		static object syncObject = new object();
 		static CurrentLineBookmark instance;
 		
 		static int startLine;
@@ -27,14 +28,15 @@ namespace ICSharpCode.SharpDevelop.Debugging
 			if (tecp != null) {
 				SetPosition(tecp.TextEditor.FileName, tecp.TextEditor.Document, makerStartLine, makerStartColumn, makerEndLine, makerEndColumn);
 			} else {
-				if (makerStartLine == 0)
-					return;
-				
-				dynamic codeView = viewContent.Control;
-				SetPosition(null, codeView.TextEditor.Document as IDocument, makerStartLine, makerStartColumn, makerEndLine, makerEndColumn);
-				codeView.IconBarManager.Bookmarks.Add(CurrentLineBookmark.instance);
-				codeView.UnfoldAndScroll(makerStartLine);
-				CurrentLineBookmark.instance.Document = codeView.TextEditor.Document as IDocument;
+				lock (syncObject) {
+					dynamic codeView = viewContent.Control;
+					var document = codeView.TextEditor.Document as IDocument;
+					SetPosition(null, document, makerStartLine, makerStartColumn, makerEndLine, makerEndColumn);
+					codeView.IconBarManager.Bookmarks.Add(CurrentLineBookmark.instance);
+					codeView.UnfoldAndScroll(makerStartLine);
+					if (document != null)
+						CurrentLineBookmark.instance.Document = document;
+				}
 			}
 		}