diff --git a/AddIns/ICSharpCode.SharpDevelop.addin b/AddIns/ICSharpCode.SharpDevelop.addin
index 015faa6fc6..0c9d9c2a90 100644
--- a/AddIns/ICSharpCode.SharpDevelop.addin
+++ b/AddIns/ICSharpCode.SharpDevelop.addin
@@ -714,64 +714,77 @@
 			
 			<ToolbarItem id = "DebuggerSeparator" type = "Separator"  />
 			
-			<Condition name="DebuggerSupports" debuggersupports = "Start">
-				<Condition name="IsProcessRunning" isdebugging="False" action="Disable">
-					<ToolbarItem id      = "Run"
-					             icon    = "Icons.16x16.RunProgramIcon"
-					             tooltip = "${res:XML.MainMenu.RunMenu.Run.Description}"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.Execute"/>
+			<ComplexCondition>
+				<Or>
+					<Condition name="IsProcessRunning" isdebugging = "False"/>
+					<Not>
+						<Condition name="DebuggerSupports" debuggersupports = "ExecutionControl"/>
+					</Not>
+				</Or>
+				<Condition name="IsProcessRunning" isdebugging = "False" action = "Disable">
+					<Condition name="DebuggerSupports" debuggersupports = "Start">
+						<ToolbarItem id      = "Run"
+						             icon    = "Icons.16x16.RunProgramIcon"
+						             tooltip = "${res:XML.MainMenu.RunMenu.Run.Description}"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.Execute"/>
+					</Condition>
+					
+					<Condition name="DebuggerSupports" debuggersupports = "StartWithoutDebugging">
+						<ToolbarItem id      = "RunWithoutDebugger"
+						             icon    = "Icons.16x16.Debug.StartWithoutDebugging"
+						             tooltip = "${res:XML.MainMenu.DebugMenu.RunWithoutDebug.Description}"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.ExecuteWithoutDebugger"/>
+					</Condition>
 				</Condition>
-			</Condition>
+			</ComplexCondition>
 			
-			<Condition name="DebuggerSupports" debuggersupports = "StartWithoutDebugging">
-				<Condition name="IsProcessRunning" isdebugging="False" action="Disable">
-					<ToolbarItem id      = "RunWithoutDebugger"
-					             icon    = "Icons.16x16.Debug.StartWithoutDebugging"
-					             tooltip = "${res:XML.MainMenu.DebugMenu.RunWithoutDebug.Description}"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.ExecuteWithoutDebugger"/>
+			<Condition name="IsProcessRunning" isdebugging = "True">
+				<Condition name="DebuggerSupports" debuggersupports = "ExecutionControl">
+					<Condition name="IsProcessRunning" isprocessrunning = "False" action = "Disable">
+						<ToolbarItem id      = "Continue"
+						             icon    = "Icons.16x16.Debug.Continue"
+						             tooltip = "${res:XML.MainMenu.DebugMenu.Continue.Description}"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.ContinueDebuggingCommand"/>
+					</Condition>
+					<Condition name="IsProcessRunning" isprocessrunning = "True" action = "Disable">
+						<ToolbarItem id      = "Break"
+						             icon    = "Icons.16x16.Debug.Break"
+						             tooltip = "${res:XML.MainMenu.DebugMenu.Break.Description}"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.BreakDebuggingCommand"/>
+					</Condition>
 				</Condition>
 			</Condition>
 			
 			<Condition name="DebuggerSupports" debuggersupports = "Stop">
-				<Condition name="IsProcessRunning" isdebugging="True" action="Disable">
+				<ComplexCondition action = "Disable">
+					<Or>
+						<Condition name="IsProcessRunning" isdebugging = "True"/>
+						<Condition name="IsProcessRunning" isprocessrunning = "True"/>
+					</Or>
 					<ToolbarItem id = "Stop"
 					             icon = "Icons.16x16.StopProcess"
 					             tooltip = "${res:XML.MainMenu.DebugMenu.Stop.Description}"
 					             class = "ICSharpCode.SharpDevelop.Project.Commands.StopDebuggingCommand"/>
-				</Condition>
+				</ComplexCondition>
 			</Condition>
 			
-			<Condition name="DebuggerSupports" debuggersupports = "ExecutionControl">
-				<ToolbarItem id = "ExecutionControlSeparator" type = "Separator"  />
-				<Condition name="IsProcessRunning"  isprocessrunning = "True" isdebugging = "True" action = "Disable">
-					<ToolbarItem id      = "Break"
-					             icon    = "Icons.16x16.Debug.Break"
-					             tooltip = "Break the debugging process"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.BreakDebuggingCommand"/>
-				</Condition>
-				<Condition name="IsProcessRunning"  isprocessrunning = "False" isdebugging = "True" action = "Disable">
-					<ToolbarItem id      = "Continue"
-					             icon    = "Icons.16x16.Debug.Continue"
-					             tooltip = "${res:XML.MainMenu.DebugMenu.Continue.Description}"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.ContinueDebuggingCommand"/>
-				</Condition>
-			</Condition>
-			
-			<Condition name="DebuggerSupports" debuggersupports = "Stepping">
-				<Condition name="IsProcessRunning"  isprocessrunning = "False" isdebugging = "True" action = "Disable">
-					<ToolbarItem id = "SteppingSeparator" type = "Separator"  />
-					<ToolbarItem id      = "Step over"
-					             icon    = "Icons.16x16.Debug.StepOver"
-					             tooltip = "Step over"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.StepDebuggingCommand"/>
-					<ToolbarItem id      = "Step into"
-					             icon    = "Icons.16x16.Debug.StepInto"
-					             tooltip = "Step into"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.StepIntoDebuggingCommand"/>
-					<ToolbarItem id      = "Step out"
-					             icon    = "Icons.16x16.Debug.StepOut"
-					             tooltip = "Step out"
-					             class   = "ICSharpCode.SharpDevelop.Project.Commands.StepOutDebuggingCommand"/>
+			<Condition name="IsProcessRunning" isdebugging = "True">
+				<Condition name="DebuggerSupports" debuggersupports = "Stepping">
+					<Condition name="IsProcessRunning" isprocessrunning = "False" action = "Disable">
+						<ToolbarItem id = "SteppingSeparator" type = "Separator"  />
+						<ToolbarItem id      = "Step over"
+						             icon    = "Icons.16x16.Debug.StepOver"
+						             tooltip = "Step over"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.StepDebuggingCommand"/>
+						<ToolbarItem id      = "Step into"
+						             icon    = "Icons.16x16.Debug.StepInto"
+						             tooltip = "Step into"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.StepIntoDebuggingCommand"/>
+						<ToolbarItem id      = "Step out"
+						             icon    = "Icons.16x16.Debug.StepOut"
+						             tooltip = "Step out"
+						             class   = "ICSharpCode.SharpDevelop.Project.Commands.StepOutDebuggingCommand"/>
+					</Condition>
 				</Condition>
 			</Condition>
 			
@@ -1225,7 +1238,7 @@
 					<MenuItem id = "ExecutionControlSeparator" type = "Separator" />
 					<Condition name="IsProcessRunning" isprocessrunning = "True" isdebugging = "True" action = "Disable">
 						<MenuItem id       = "Break"
-						          label    = "Break"
+						          label    = "${res:XML.MainMenu.DebugMenu.Break}"
 						          icon     = "Icons.16x16.Debug.Break"
 						          shortcut = "Control|Alt|B"
 						          class    = "ICSharpCode.SharpDevelop.Project.Commands.BreakDebuggingCommand"/>
diff --git a/src/AddIns/DisplayBindings/FormDesigner/Project/Src/FormDesigner/FormDesignerSecondaryDisplayBinding.cs b/src/AddIns/DisplayBindings/FormDesigner/Project/Src/FormDesigner/FormDesignerSecondaryDisplayBinding.cs
index 638cbf6f57..782d0b1e1b 100644
--- a/src/AddIns/DisplayBindings/FormDesigner/Project/Src/FormDesigner/FormDesignerSecondaryDisplayBinding.cs
+++ b/src/AddIns/DisplayBindings/FormDesigner/Project/Src/FormDesigner/FormDesignerSecondaryDisplayBinding.cs
@@ -60,7 +60,7 @@ namespace ICSharpCode.FormDesigner
 		{
 			// Simple test for fully qualified name
 			foreach (IReturnType baseType in c.BaseTypes) {
-				if (baseType.Name == "System.Windows.Forms.Form" || baseType.Name == "System.Windows.Forms.UserControl") {
+				if (baseType.FullyQualifiedName == "System.Windows.Forms.Form" || baseType.FullyQualifiedName == "System.Windows.Forms.UserControl") {
 					return true;
 				}
 			}
diff --git a/src/AddIns/DisplayBindings/XmlEditor/Project/Src/XmlView.cs b/src/AddIns/DisplayBindings/XmlEditor/Project/Src/XmlView.cs
index 913d205d6a..df039a480f 100644
--- a/src/AddIns/DisplayBindings/XmlEditor/Project/Src/XmlView.cs
+++ b/src/AddIns/DisplayBindings/XmlEditor/Project/Src/XmlView.cs
@@ -196,12 +196,31 @@ namespace ICSharpCode.XmlEditor
 			}
 		}
 		
+		// ParserUpdateThread uses the text property via IEditable, I had an exception
+		// because multiple threads were accessing the GapBufferStrategy at the same time.
+		
+		string GetText()
+		{
+			return xmlEditor.Document.TextContent;
+		}
+		
+		void SetText(string value)
+		{
+			xmlEditor.Document.TextContent = value;
+		}
+		
 		public string Text {
 			get {
-				return xmlEditor.Document.TextContent;
+				if (WorkbenchSingleton.InvokeRequired)
+					return (string)WorkbenchSingleton.SafeThreadCall(this, "GetText", null);
+				else
+					return GetText();
 			}
 			set {
-				xmlEditor.Document.TextContent = value;
+				if (WorkbenchSingleton.InvokeRequired)
+					WorkbenchSingleton.SafeThreadCall(this, "SetText", value);
+				else
+					SetText(value);
 			}
 		}
 		
diff --git a/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Debugger.AddIn.addin b/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Debugger.AddIn.addin
index 7d00cee41a..00ffadce21 100644
--- a/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Debugger.AddIn.addin
+++ b/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Debugger.AddIn.addin
@@ -4,7 +4,10 @@
 	</Runtime>
 
 	<Path name="/SharpDevelop/Services/DebuggerService/Debugger">
-		<Class id="DefaultDebugger" class="ICSharpCode.SharpDevelop.Services.WindowsDebugger"/>
+		<Debugger id="DefaultDebugger"
+		          supportsStepping = "true"
+		          supportsExecutionControl = "true"
+		          class="ICSharpCode.SharpDevelop.Services.WindowsDebugger"/>
 	</Path>
 	
 	<!--<Path name = "/SharpDevelop/Workbench/MainMenu/Debug">
diff --git a/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Service/WindowsDebugger.cs b/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Service/WindowsDebugger.cs
index 3f37573b5e..6dcdfa1565 100644
--- a/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Service/WindowsDebugger.cs
+++ b/src/AddIns/Misc/Debugger/Debugger.AddIn/Project/Src/Service/WindowsDebugger.cs
@@ -102,36 +102,15 @@ namespace ICSharpCode.SharpDevelop.Services
 						   processStartInfo.Arguments);
 		}
 
-		public bool SupportsStart {
-			get {
-				return true;
-			}
-		}
-
 		public void StartWithoutDebugging(ProcessStartInfo processStartInfo)
 		{
-			System.Diagnostics.Process process;
-			process = new System.Diagnostics.Process();
-			process.StartInfo = processStartInfo;
-			process.Start();
-		}
-
-		public bool SupportsStartWithoutDebugging {
-			get {
-				return true;
-			}
+			System.Diagnostics.Process.Start(processStartInfo);
 		}
 
 		public void Stop()
 		{
 			debugger.Terminate();
 		}
-
-		public bool SupportsStop {
-			get {
-				return true;
-			}
-		}
 		
 		// ExecutionControl:
 		
@@ -145,12 +124,6 @@ namespace ICSharpCode.SharpDevelop.Services
 			debugger.Continue();
 		}
 
-		public bool SupportsExecutionControl {
-			get {
-				return true;
-			}
-		}
-
 		// Stepping:
 
 		public void StepInto()
@@ -180,12 +153,6 @@ namespace ICSharpCode.SharpDevelop.Services
 			}
 		}
 
-		public bool SupportsStepping {
-			get {
-				return true;
-			}
-		}
-
 		public event EventHandler DebugStarted;
 
 		protected virtual void OnDebugStarted(EventArgs e) 
@@ -352,6 +319,7 @@ namespace ICSharpCode.SharpDevelop.Services
 				exceptionHistory.Clear();
 				OnDebugStopped(EventArgs.Empty);
 				isDebuggingCache = false;
+				isProcessRunningCache = false;
 			}
 		}
 
diff --git a/src/Libraries/ICSharpCode.TextEditor/Project/ICSharpCode.TextEditor.csproj b/src/Libraries/ICSharpCode.TextEditor/Project/ICSharpCode.TextEditor.csproj
index b8acc66da3..72124dbbfc 100644
--- a/src/Libraries/ICSharpCode.TextEditor/Project/ICSharpCode.TextEditor.csproj
+++ b/src/Libraries/ICSharpCode.TextEditor/Project/ICSharpCode.TextEditor.csproj
@@ -22,7 +22,7 @@
     <AllowUnsafeBlocks>False</AllowUnsafeBlocks>
     <CheckForOverflowUnderflow>True</CheckForOverflowUnderflow>
     <OutputPath>..\..\..\..\bin\</OutputPath>
-    <TreatWarningsAsErrors>False</TreatWarningsAsErrors>
+    <DefineConstants>DEBUG</DefineConstants>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugSymbols>False</DebugSymbols>
@@ -181,4 +181,4 @@
     <Compile Include="Src\Document\TextBufferStrategy\PieceTableTextBufferStrategy.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSHARP.Targets" />
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/TextBufferStrategy/GapTextBufferStrategy.cs b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/TextBufferStrategy/GapTextBufferStrategy.cs
index 8e24abe73b..b2f8605640 100644
--- a/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/TextBufferStrategy/GapTextBufferStrategy.cs
+++ b/src/Libraries/ICSharpCode.TextEditor/Project/Src/Document/TextBufferStrategy/GapTextBufferStrategy.cs
@@ -12,6 +12,16 @@ namespace ICSharpCode.TextEditor.Document
 {
 	public class GapTextBufferStrategy : ITextBufferStrategy
 	{
+		#if DEBUG
+		int creatorThread = System.Threading.Thread.CurrentThread.ManagedThreadId;
+		
+		void CheckThread()
+		{
+			if (System.Threading.Thread.CurrentThread.ManagedThreadId != creatorThread)
+				throw new InvalidOperationException("GapTextBufferStategy is not thread-safe!");
+		}
+		#endif
+		
 		char[] buffer = new char[0];
 		
 		int gapBeginOffset = 0;
@@ -48,6 +58,9 @@ namespace ICSharpCode.TextEditor.Document
 		
 		public string GetText(int offset, int length) 
 		{
+			#if DEBUG
+			CheckThread();
+			#endif
 			int end = offset + length;
 			
 			if (end < gapBeginOffset) {
diff --git a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
index 98d9f135d4..35c681b5f3 100644
--- a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
+++ b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
@@ -689,6 +689,7 @@
     <Compile Include="Src\TextEditor\SearchAndReplace\Engine\SearchStrategy\BoyerMooreSearchStrategy.cs" />
     <Compile Include="Src\Gui\BrowserDisplayBinding\BrowserCommands.cs" />
     <Compile Include="Src\Gui\BrowserDisplayBinding\BrowserLocationConditionEvaluator.cs" />
+    <Compile Include="Src\Services\Debugger\DebuggerDoozer.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\Libraries\DockPanel_Src\WinFormsUI\WinFormsUI.csproj">
diff --git a/src/Main/Base/Project/Src/Dom/Implementations/SearchClassReturnType.cs b/src/Main/Base/Project/Src/Dom/Implementations/SearchClassReturnType.cs
index 31840b66e7..97fbbf8121 100644
--- a/src/Main/Base/Project/Src/Dom/Implementations/SearchClassReturnType.cs
+++ b/src/Main/Base/Project/Src/Dom/Implementations/SearchClassReturnType.cs
@@ -59,16 +59,21 @@ namespace ICSharpCode.SharpDevelop.Dom
 			return declaringClass.GetHashCode() ^ name.GetHashCode();
 		}
 		
-		// TODO: Cache BaseType until a new CompilationUnit is generated (static counter in ParserService)
 		bool isSearching;
+		IReturnType cachedBaseType;
+		int cachedVersion = -1;
 		
 		public override IReturnType BaseType {
 			get {
 				if (isSearching)
 					return null;
+				if (pc.Version == cachedVersion)
+					return cachedBaseType;
 				try {
 					isSearching = true;
-					return pc.SearchType(name, declaringClass, caretLine, caretColumn);
+					cachedBaseType = pc.SearchType(name, declaringClass, caretLine, caretColumn);
+					cachedVersion = pc.Version;
+					return cachedBaseType;
 				} finally {
 					isSearching = false;
 				}
diff --git a/src/Main/Base/Project/Src/Gui/Pads/ClassBrowser/ClassBrowser.cs b/src/Main/Base/Project/Src/Gui/Pads/ClassBrowser/ClassBrowser.cs
index 1d35d9a648..42e96bf7bc 100644
--- a/src/Main/Base/Project/Src/Gui/Pads/ClassBrowser/ClassBrowser.cs
+++ b/src/Main/Base/Project/Src/Gui/Pads/ClassBrowser/ClassBrowser.cs
@@ -75,19 +75,8 @@ namespace ICSharpCode.SharpDevelop.Gui
 		
 		void UpdateToolbars()
 		{
-			foreach (object o in toolStrip.Items) {
-				if (o is IStatusUpdate) {
-					((IStatusUpdate)o).UpdateStatus();
-				}
-			}
-			toolStrip.Refresh();
-			
-			foreach (object o in searchStrip.Items) {
-				if (o is IStatusUpdate) {
-					((IStatusUpdate)o).UpdateStatus();
-				}
-			}
-			searchStrip.Refresh();
+			ToolbarService.UpdateToolbar(toolStrip);
+			ToolbarService.UpdateToolbar(searchStrip);
 		}
 		
 		public ClassBrowser()
diff --git a/src/Main/Base/Project/Src/Gui/Workbench/DefaultWorkbench.cs b/src/Main/Base/Project/Src/Gui/Workbench/DefaultWorkbench.cs
index de8492e548..e90d2f9b80 100644
--- a/src/Main/Base/Project/Src/Gui/Workbench/DefaultWorkbench.cs
+++ b/src/Main/Base/Project/Src/Gui/Workbench/DefaultWorkbench.cs
@@ -469,37 +469,16 @@ namespace ICSharpCode.SharpDevelop.Gui
 		void UpdateToolbars()
 		{
 			if (ToolBars != null) {
-				foreach (ToolStrip ToolStrip in ToolBars) {
-					bool doRefresh = false;
-					foreach (ToolStripItem item in ToolStrip.Items) {
-						bool wasVisible = item.Visible;
-						if (item is ToolBarCommand) {
-							ToolBarCommand toolBarCommand = (ToolBarCommand)item;
-							doRefresh |= toolBarCommand.LastEnabledStatus != toolBarCommand.CurrentEnableStatus;
-							toolBarCommand.UpdateStatus();
-						} else {
-							if (item is IStatusUpdate) {
-								((IStatusUpdate)item).UpdateStatus();
-							}
-						}
-						doRefresh |= wasVisible != item.Visible;
-					}
-					if (doRefresh) {
-						ToolStrip.Refresh();
-					}
+				foreach (ToolStrip toolStrip in ToolBars) {
+					ToolbarService.UpdateToolbar(toolStrip);
 				}
 			}
 		}
 		
-		// this method simply copies over the enabled state of the toolbar,
-		// this assumes that no item is inserted or removed.
-		// TODO : make this method more add-in tree like, currently with Windows.Forms
-		//        toolbars this is not possible. (drawing fragments, slow etc.)
 		void CreateToolBars()
 		{
 			if (ToolBars == null) {
 				ToolBars = ToolbarService.CreateToolbars(this, "/SharpDevelop/Workbench/ToolBar");
-				UpdateToolbars();
 			}
 		}
 		
diff --git a/src/Main/Base/Project/Src/Internal/ConditionEvaluators/DebuggerSupportsEvaluator.cs b/src/Main/Base/Project/Src/Internal/ConditionEvaluators/DebuggerSupportsEvaluator.cs
index fe62b77416..524ae2ce0c 100644
--- a/src/Main/Base/Project/Src/Internal/ConditionEvaluators/DebuggerSupportsEvaluator.cs
+++ b/src/Main/Base/Project/Src/Internal/ConditionEvaluators/DebuggerSupportsEvaluator.cs
@@ -16,24 +16,21 @@ namespace ICSharpCode.Core
 	{
 		public bool IsValid(object caller, Condition condition)
 		{
-			IDebugger debugger = DebuggerService.IsDebuggerLoaded ? DebuggerService.CurrentDebugger : new DefaultDebugger();
-			if (debugger != null) {
-				switch (condition.Properties["debuggersupports"]) {
-					case "Start":
-						return debugger.SupportsStart;
-					case "StartWithoutDebugging":
-						return debugger.SupportsStartWithoutDebugging;
-					case "Stop":
-						return debugger.SupportsStop;
-					case "ExecutionControl":
-						return debugger.SupportsExecutionControl;
-					case "Stepping":
-						return debugger.SupportsStepping;
-					default:
-						throw new ArgumentException("Unknown debugger support for : >" + condition.Properties["debuggersupports"] + "< please fix addin file.", "debuggersupports");
-				}
+			DebuggerDescriptor debugger = DebuggerService.Descriptor;
+			switch (condition.Properties["debuggersupports"]) {
+				case "Start":
+					return (debugger != null) ? debugger.SupportsStart : true;
+				case "StartWithoutDebugging":
+					return (debugger != null) ? debugger.SupportsStartWithoutDebugging : true;
+				case "Stop":
+					return (debugger != null) ? debugger.SupportsStop : true;
+				case "ExecutionControl":
+					return (debugger != null) ? debugger.SupportsExecutionControl : false;
+				case "Stepping":
+					return (debugger != null) ? debugger.SupportsStepping : false;
+				default:
+					throw new ArgumentException("Unknown debugger support for : >" + condition.Properties["debuggersupports"] + "< please fix addin file.", "debuggersupports");
 			}
-			return false;
 		}
 	}
 }
diff --git a/src/Main/Base/Project/Src/Services/Debugger/DebuggerDoozer.cs b/src/Main/Base/Project/Src/Services/Debugger/DebuggerDoozer.cs
new file mode 100644
index 0000000000..9472873951
--- /dev/null
+++ b/src/Main/Base/Project/Src/Services/Debugger/DebuggerDoozer.cs
@@ -0,0 +1,80 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt">2002-2005 AlphaSierraPapa</copyright>
+//     <license see="prj:///doc/license.txt">GNU General Public License</license>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections;
+
+namespace ICSharpCode.Core
+{
+	public class DebuggerDoozer : IDoozer
+	{
+		/// <summary>
+		/// Gets if the doozer handles codon conditions on its own.
+		/// If this property return false, the item is excluded when the condition is not met.
+		/// </summary>
+		public bool HandleConditions {
+			get {
+				return false;
+			}
+		}
+		
+		public object BuildItem(object caller, Codon codon, ArrayList subItems)
+		{
+			return new DebuggerDescriptor(codon);
+		}
+	}
+	
+	public class DebuggerDescriptor
+	{
+		Codon codon;
+		
+		public DebuggerDescriptor(Codon codon)
+		{
+			this.codon = codon;
+		}
+		
+		IDebugger debugger;
+		
+		public IDebugger Debugger {
+			get {
+				if (debugger == null)
+					debugger = (IDebugger)codon.AddIn.CreateObject(codon.Properties["class"]);
+				return debugger;
+			}
+		}
+		
+		public bool SupportsStart {
+			get {
+				return codon.Properties["supportsStart"] != "false";
+			}
+		}
+		
+		public bool SupportsStartWithoutDebugging {
+			get {
+				return codon.Properties["supportsStartWithoutDebugger"] != "false";
+			}
+		}
+		
+		public bool SupportsStop {
+			get {
+				return codon.Properties["supportsStop"] != "false";
+			}
+		}
+		
+		public bool SupportsStepping {
+			get {
+				return codon.Properties["supportsStepping"] == "true";
+			}
+		}
+		
+		public bool SupportsExecutionControl {
+			get {
+				return codon.Properties["supportsExecutionControl"] == "true";
+			}
+		}
+	}
+}
diff --git a/src/Main/Base/Project/Src/Services/Debugger/DebuggerService.cs b/src/Main/Base/Project/Src/Services/Debugger/DebuggerService.cs
index 73805e59ff..1006575877 100644
--- a/src/Main/Base/Project/Src/Services/Debugger/DebuggerService.cs
+++ b/src/Main/Base/Project/Src/Services/Debugger/DebuggerService.cs
@@ -26,7 +26,7 @@ namespace ICSharpCode.Core
 	public static class DebuggerService
 	{
 		static IDebugger   currentDebugger;
-		static ArrayList   debuggers;
+		static DebuggerDescriptor[] debuggers;
 		static string      oldLayoutConfiguration = "Default";
 
 		static DebuggerService()
@@ -40,18 +40,23 @@ namespace ICSharpCode.Core
 			BM.BookmarkManager.Removed += BookmarkRemoved;
 		}
 		
+		static void GetDescriptors()
+		{
+			if (debuggers == null) {
+				debuggers = (DebuggerDescriptor[])AddInTree.BuildItems("/SharpDevelop/Services/DebuggerService/Debugger", null, false).ToArray(typeof(DebuggerDescriptor));
+			}
+		}
+		
 		static IDebugger GetCompatibleDebugger()
 		{
+			GetDescriptors();
 			IProject project = null;
 			if (ProjectService.OpenSolution != null) {
 				project = ProjectService.OpenSolution.StartupProject;
 			}
-			if (debuggers == null) {
-				debuggers = AddInTree.BuildItems("/SharpDevelop/Services/DebuggerService/Debugger", null, false);
-			}
-			foreach (IDebugger d in debuggers) {
-				if (d.CanDebug(project)) {
-					return d;
+			foreach (DebuggerDescriptor d in debuggers) {
+				if (d.Debugger.CanDebug(project)) {
+					return d.Debugger;
 				}
 			}
 			return new DefaultDebugger();
@@ -59,8 +64,8 @@ namespace ICSharpCode.Core
 		
 		/// <summary>
 		/// Gets the current debugger. The debugger addin is loaded on demand; so if you
-		/// just want to check a property like IsDebugging, use <see cref="LoadedDebugger"/>
-		/// instead.
+		/// just want to check a property like IsDebugging, check <see cref="IsDebuggerLoaded"/>
+		/// before using this property.
 		/// </summary>
 		public static IDebugger CurrentDebugger {
 			get {
@@ -73,6 +78,15 @@ namespace ICSharpCode.Core
 			}
 		}
 		
+		public static DebuggerDescriptor Descriptor {
+			get {
+				GetDescriptors();
+				if (debuggers.Length > 0)
+					return debuggers[0];
+				return null;
+			}
+		}
+		
 		/// <summary>
 		/// Returns true if debugger is already loaded.
 		/// </summary>
diff --git a/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs b/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs
index 3766e89d88..f10aeeafca 100644
--- a/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs
+++ b/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs
@@ -61,24 +61,9 @@ namespace ICSharpCode.Core
 			OnDebugStopped(EventArgs.Empty);
 		}
 
-		public bool SupportsStart {
-			get {
-				return true;
-			}
-		}
-
 		public void StartWithoutDebugging(ProcessStartInfo processStartInfo)
 		{
-			Process process;
-			process = new Process();
-			process.StartInfo = processStartInfo;
-			process.Start();
-		}
-
-		public bool SupportsStartWithoutDebugging {
-			get {
-				return true;
-			}
+			Process.Start(processStartInfo);
 		}
 
 		public void Stop()
@@ -91,12 +76,6 @@ namespace ICSharpCode.Core
 				attachedProcess = null;
 			}
 		}
-
-		public bool SupportsStop {
-			get {
-				return true;
-			}
-		}
 		
 		// ExecutionControl:
 		
@@ -109,13 +88,6 @@ namespace ICSharpCode.Core
 		{
 			throw new NotSupportedException();
 		}
-
-		public bool SupportsExecutionControl {
-			get {
-				return false;
-			}
-		}
-
 		// Stepping:
 
 		public void StepInto()
@@ -133,12 +105,6 @@ namespace ICSharpCode.Core
 			throw new NotSupportedException();
 		}
 
-		public bool SupportsStepping {
-			get {
-				return false;
-			}
-		}
-
 		public event EventHandler DebugStarted;
 
 		protected virtual void OnDebugStarted(EventArgs e) 
diff --git a/src/Main/Base/Project/Src/Services/Debugger/IDebugger.cs b/src/Main/Base/Project/Src/Services/Debugger/IDebugger.cs
index f58a7d261c..c7cde6047b 100644
--- a/src/Main/Base/Project/Src/Services/Debugger/IDebugger.cs
+++ b/src/Main/Base/Project/Src/Services/Debugger/IDebugger.cs
@@ -9,7 +9,7 @@ using System;
 using ICSharpCode.SharpDevelop.Project;
 using System.Diagnostics;
 
-namespace ICSharpCode.Core 
+namespace ICSharpCode.Core
 {
 	public interface IDebugger : IDisposable
 	{
@@ -29,71 +29,48 @@ namespace ICSharpCode.Core
 		}
 		
 		bool CanDebug(IProject project);
-
+		
 		/// <summary>
 		/// Starts process and attaches debugger
 		/// </summary>
 		void Start(ProcessStartInfo processStartInfo);
-
-		bool SupportsStart {
-			get;
-		}
-
-		/// <summary>
-		/// Starts process and does not attach debugger
-		/// </summary>
+		
 		void StartWithoutDebugging(ProcessStartInfo processStartInfo);
-
-		bool SupportsStartWithoutDebugging {
-			get;
-		}
-
+		
 		/// <summary>
 		/// Stops/terminates attached process
 		/// </summary>
 		void Stop();
-
-		bool SupportsStop {
-			get;
-		}
 		
 		// ExecutionControl:
 		
 		void Break();
 		
 		void Continue();
-
-		bool SupportsExecutionControl {
-			get;
-		}
-
+		
 		// Stepping:
-
+		
 		void StepInto();
-
+		
 		void StepOver();
-
+		
 		void StepOut();
-
-		bool SupportsStepping {
-			get;
-		}
 		
 		/// <summary>
 		/// Gets the current value of the variable as string that can be displayed in tooltips.
 		/// </summary>
 		string GetValueAsString(string variable);
-
+		
 		/// <summary>
 		/// Ocurrs after the debugger has started.
 		/// </summary>
 		event EventHandler DebugStarted;
-
+		
 		/// <summary>
 		/// Ocurrs when the value of IsProcessRunning changes.
 		/// </summary>
 		event EventHandler IsProcessRunningChanged;
-
+		
 		/// <summary>
 		/// Ocurrs after the debugging of program is finished.
 		/// </summary>
diff --git a/src/Main/Base/Project/Src/Services/ParserService/DefaultProjectContent.cs b/src/Main/Base/Project/Src/Services/ParserService/DefaultProjectContent.cs
index 0d587e7338..39640ef71f 100644
--- a/src/Main/Base/Project/Src/Services/ParserService/DefaultProjectContent.cs
+++ b/src/Main/Base/Project/Src/Services/ParserService/DefaultProjectContent.cs
@@ -37,6 +37,21 @@ namespace ICSharpCode.Core
 		List<Dictionary<string, NamespaceStruct>> namespaces = new List<Dictionary<string, NamespaceStruct>>();
 		protected XmlDoc xmlDoc = new XmlDoc();
 		IUsing defaultImports;
+		int version;
+		
+		public int Version {
+			get {
+				return version;
+			}
+		}
+		
+		void IncrementVersion()
+		{
+			if (version == int.MaxValue)
+				version = 1;
+			else
+				version += 1;
+		}
 		
 		public IUsing DefaultImports {
 			get {
@@ -190,6 +205,7 @@ namespace ICSharpCode.Core
 		
 		public void AddClassToNamespaceList(IClass addClass)
 		{
+			IncrementVersion();
 			lock (namespaces) {
 				AddClassToNamespaceListInternal(addClass);
 			}
@@ -303,6 +319,7 @@ namespace ICSharpCode.Core
 		
 		public void UpdateCompilationUnit(ICompilationUnit oldUnit, ICompilationUnit parserOutput, string fileName, bool updateCommentTags)
 		{
+			IncrementVersion();
 			if (updateCommentTags) {
 				TaskService.UpdateCommentTags(fileName, parserOutput.TagComments);
 			}
diff --git a/src/Main/Base/Project/Src/Services/ParserService/IProjectContent.cs b/src/Main/Base/Project/Src/Services/ParserService/IProjectContent.cs
index 5834d784a0..909ebe945d 100644
--- a/src/Main/Base/Project/Src/Services/ParserService/IProjectContent.cs
+++ b/src/Main/Base/Project/Src/Services/ParserService/IProjectContent.cs
@@ -55,6 +55,14 @@ namespace ICSharpCode.Core
 			get;
 		}
 		
+		/// <summary>
+		/// Gets the version number of the project content.
+		/// Is incremented whenever a CompilationUnit is updated.
+		/// </summary>
+		int Version {
+			get;
+		}
+		
 		string GetXmlDocumentation(string memberTag);
 		
 		void AddClassToNamespaceList(IClass addClass);
diff --git a/src/Main/Core/Project/Src/AddInTree/AddIn/DefaultDoozers/MenuItem/Gui/MenuCommand.cs b/src/Main/Core/Project/Src/AddInTree/AddIn/DefaultDoozers/MenuItem/Gui/MenuCommand.cs
index 85b0fe5bc2..c647535ff9 100644
--- a/src/Main/Core/Project/Src/AddInTree/AddIn/DefaultDoozers/MenuItem/Gui/MenuCommand.cs
+++ b/src/Main/Core/Project/Src/AddInTree/AddIn/DefaultDoozers/MenuItem/Gui/MenuCommand.cs
@@ -109,8 +109,10 @@ namespace ICSharpCode.Core
 		protected override void OnClick(System.EventArgs e)
 		{
 			base.OnClick(e);
-			if (codon != null) {
-				Command.Run();
+			if (GetVisible() && Enabled) {
+				if (codon != null) {
+					Command.Run();
+				}
 			}
 		}
 		
@@ -136,14 +138,18 @@ namespace ICSharpCode.Core
 			}
 		}
 		
+		bool GetVisible()
+		{
+			return codon.GetFailedAction(caller) != ConditionFailedAction.Exclude;
+		}
+		
 		public virtual void UpdateStatus()
 		{
 			if (codon != null) {
 				if (Image == null && codon.Properties.Contains("icon")) {
 					Image = ResourceService.GetBitmap(codon.Properties["icon"]);
 				}
-				ConditionFailedAction failedAction = codon.GetFailedAction(caller);
-				Visible = failedAction != ConditionFailedAction.Exclude;
+				Visible = GetVisible();
 				
 				if (localizedText == null) {
 					localizedText = codon.Properties["label"];
diff --git a/src/Main/Core/Project/Src/Services/ToolBarService/ToolBarService.cs b/src/Main/Core/Project/Src/Services/ToolBarService/ToolBarService.cs
index df175a1e9c..3797cc216f 100644
--- a/src/Main/Core/Project/Src/Services/ToolBarService/ToolBarService.cs
+++ b/src/Main/Core/Project/Src/Services/ToolBarService/ToolBarService.cs
@@ -70,6 +70,7 @@ namespace ICSharpCode.Core
 					((IStatusUpdate)item).UpdateStatus();
 				}
 			}
+			toolStrip.Refresh();
 		}
 	}
 }
diff --git a/src/Main/StartUp/Project/SharpDevelopMain.cs b/src/Main/StartUp/Project/SharpDevelopMain.cs
index 196df25096..c45bfadf3b 100644
--- a/src/Main/StartUp/Project/SharpDevelopMain.cs
+++ b/src/Main/StartUp/Project/SharpDevelopMain.cs
@@ -168,6 +168,7 @@ namespace ICSharpCode.SharpDevelop
 			AddInTree.Doozers.Add("SyntaxMode", new ICSharpCode.SharpDevelop.DefaultEditor.Codons.SyntaxModeDoozer());
 			AddInTree.Doozers.Add("BrowserSchemeExtension", new ICSharpCode.SharpDevelop.BrowserDisplayBinding.SchemeExtensionDoozer());
 			AddInTree.Doozers.Add("CodeCompletionBinding", new ICSharpCode.SharpDevelop.DefaultEditor.Gui.Editor.CodeCompletionBindingDoozer());
+			AddInTree.Doozers.Add("Debugger", new DebuggerDoozer());
 			
 			MenuCommand.LinkCommandCreator = delegate(string link) { return new LinkCommand(link); };