1. How do I turn off the close button feature on one Tab? I don't want the user to be able to close the first tab.

2. When I attempt to add an event for NewItemRequested, I get an error.
- if I type the event in Xaml, and right click to "Go to Definiation" it says "Error.. Cannot Navigate to definition"
- if I try the same thing in the event manager. (double click in event) I get System.ArgumentNullException (full error below)
- other events such as OnFocus work fine.




System.ArgumentNullException
Value cannot be null.
Parameter name: inputString
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CCodeModelBase.ValidateIdentifier(String inputString, Boolean allowDotted, Boolean allowOperatorKeyword)
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CCodeFunction.AddParameter(String bstrName, Object vtType, Object vtPosition)
at EnvDTE.CodeFunction.AddParameter(String Name, Object Type, Object Position)
at Microsoft.VisualStudio.ExpressionHost.Platform.DTECodeContext.CreateFunction(CodeClass codeClass, IHostCodeEvent codeEvent, String methodName, String location)
at Microsoft.VisualStudio.ExpressionHost.Platform.DTECodeContext.Microsoft.Expression.DesignHost.IHostCodeContext.CreateMethod(IHostCodeEvent codeEvent, String methodName, String initialStatements)
at Microsoft.Expression.DesignHost.Isolation.Remoting.RemoteHostCodeContext.<>c__DisplayClassd.<Microsoft.Expression.DesignHost.Isolation.Remoting.IRemoteHostCodeContext.CreateMethod>b__c()
at Microsoft.Expression.DesignHost.Isolation.Remoting.ThreadMarshaler.<>c__DisplayClass2a`1.<MarshalIn>b__29()
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.Call.InvokeWorker()

System.ArgumentNullException
Value cannot be null.
Parameter name: inputString

Server stack trace:
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.WaitForCompletion(NestedCallContext nestedCallContext, BlockingCall call, WaitHandle timeoutSignal)
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.MarshalInSynchronous(Action action, Int32 targetApartmentId, CancellationToken cancelToken, CallModality callModality, String methodName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.MarshalIn(Action action, Int32 targetApartmentId, CancellationToken cancelToken, CallSynchronizationMode syncMode, CallModality callModality, String methodName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.ThreadMarshaler.MarshalIn(IRemoteObject targetObject, Action action, CallSynchronizationMode syncMode, CallModality callModality, ApartmentState apartmentState, String memberName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.ThreadMarshaler.MarshalIn[TResult](IRemoteObject targetObject, Func`1 func, CallModality callModality, ApartmentState apartmentState, String memberName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.RemoteHostCodeContext.Microsoft.Expression.DesignHost.Isolation.Remoting.IRemoteHostCodeContext.CreateMethod(String eventName, RemoteHostParameter[] parameters, String returnType, String methodName, String initialStatements)
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg)

Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at Microsoft.Expression.DesignHost.Isolation.Remoting.IRemoteHostCodeContext.CreateMethod(String eventName, RemoteHostParameter[] parameters, String returnType, String methodName, String initialStatements)
at Microsoft.Expression.DesignHost.Isolation.Remoting.LocalHostCodeContext.<>c__DisplayClass10.<Microsoft.Expression.DesignHost.IHostCodeContext.CreateMethod>b__f(IRemoteHostCodeContext cxt)
at Microsoft.Expression.DesignHost.Isolation.Remoting.ThreadMarshaler.<>c__DisplayClassa`2.<MarshalOut>b__9()
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.Call.InvokeWorker()

System.ArgumentNullException
Value cannot be null.
Parameter name: inputString
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.WaitForCompletion(NestedCallContext nestedCallContext, BlockingCall call, WaitHandle timeoutSignal)
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.MarshalOutSynchronous(Action action, Int32 targetApartmentId, WaitHandle aborted, WaitHandle timeoutSignal, CancellationToken cancelToken, String methodName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.STAMarshaler.MarshalOut(Action action, Int32 targetApartmentId, WaitHandle aborted, CancellationToken cancelToken, CallSynchronizationMode syncMode, WaitHandle timeoutSignal, String methodName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.ThreadMarshaler.MarshalOut[TValue](RemoteHandle`1 targetObject, Action action, CallSynchronizationMode syncMode, ApartmentState apartmentState, String methodName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.ThreadMarshaler.MarshalOut[TResult,TValue](RemoteHandle`1 targetObject, Func`2 func, CallSynchronizationMode syncMode, ApartmentState apartmentState, String methodName, String filePath, Int32 lineNumber)
at Microsoft.Expression.DesignHost.Isolation.Remoting.LocalHostCodeContext.Microsoft.Expression.DesignHost.IHostCodeContext.CreateMethod(IHostCodeEvent codeEvent, String methodName, String initialStatements)
at Microsoft.Expression.DesignSurface.UserInterface.PropertyInspector.CodeContext.CreateEventHandler(ISourceItemContext item, String typeName, IEvent eventKey, String methodName)
at Microsoft.Expression.DesignSurface.UserInterface.PropertyInspector.EventHandlerProvider.CreateEventHandler(IEvent eventKey, String methodName)
at Microsoft.Expression.DesignSurface.UserInterface.PropertyInspector.EventHandlerModel.SetMethodName(String newName)
at Microsoft.Expression.DesignSurface.UserInterface.PropertyInspector.EventHandlerModel.GenerateAndCommit()
at Microsoft.Expression.DesignSurface.UserInterface.PropertyInspector.EventHandlerModel.<get_GenerateAndCommitCommand>b__1(Object arg)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.Run()
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at Microsoft.Expression.DesignHost.Isolation.DesignerProcess.RunApplication()
at Microsoft.Expression.DesignHost.Isolation.DesignerProcess.<>c__DisplayClass2.<Main>b__0()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()