[Audited]
public virtual ActionResult a(){return whatever}

public virtual ActionResult b(int? shipHighlightGreen = null)
{ 
return whatever
}

ERROR 2017-07-25 12:12:51,452 [51   ] MyProject.Web.Controllers.OrderController   - The parameters dictionary contains an invalid entry for parameter 'shiphighlightGreen' for method 'System.Web.Mvc.ActionResult Modal_Order_Details(Int32, Boolean, System.Nullable`1[System.Int32], System.Nullable`1[System.Int32])' in 'Castle.Proxies.OrderControllerProxy'. The dictionary contains a value of type 'System.Reflection.Missing', but the parameter requires a value of type 'System.Nullable`1[System.Int32]'.
ParameterName:parameters
System.ArgumentException: The parameters dictionary contains an invalid entry for parameter 'shiphighlightGreen' for method 'System.Web.Mvc.ActionResult Modal_Order_Details(Int32, Boolean, System.Nullable`1[System.Int32], System.Nullable`1[System.Int32])' in 'Castle.Proxies.OrderControllerProxy'. The dictionary contains a value of type 'System.Reflection.Missing', but the parameter requires a value of type 'System.Nullable`1[System.Int32]'.
ParameterName:parameters
   Location System.Web.Mvc.ActionDescriptor.ExtractParameterFromDictionary(ParameterInfo parameterInfo, IDictionary`2 parameters, MethodInfo methodInfo)
   Location System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
   Location System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState)
   Location System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult)
   Location System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult)
   Location System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult)
   Location System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult)
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c()
   Location System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult)

public virtual ActionResult b(int shipHighlightGreen = -1)
{ 
return whatever
}