Reproducible Crash: 5.2 beta 2: System.NullReferenceException: Object reference not set to an instan

I typed Show Help into the command bar, and tried to drag the command onto the shortcuts bar. Logos crashes every time, with this stack trace.

2013-10-23 21:47:30.3047 1 Error OurApp Unhandled exception: System.NullReferenceException: Object reference not set to an instance of an object.
 at LDLS4.AppModel.PrepareNavigationRequest(NavigationRequest request, NavigationTarget target)
 at LDLS4.AppModel.CreatePanel(NavigationRequest request)
 at LDLS4.AppCommands.PanelKindAppCommand.CreatePanelCore()
 at LDLS4.AppModel.<ConvertDataObjectToNewPanel>b__83(AppCommand x)
 at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
 at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
 at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
 at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
 at LDLS4.AppModel.ConvertDataObjectToNewPanel(IDataObject data)
 at LDLS4.WindowModelBase.CreateDragWindowTabs(IDataObject dragData, Scope& scopePanelDrag)
 at LDLS4.OurWindowBase.OurWindowBase_DragStarted(Object sender, DragStartEventArgs e)
 at Libronix.Utility.Windows.DragStartEventHandler.Invoke(Object sender, DragStartEventArgs e)
 at Libronix.Utility.Windows.DragStartEventArgs.RaiseStarted(Object sender, DragStartEventArgs e)
 at Libronix.Utility.Windows.DragDropSource.DoDragDrop(DependencyObject d, Object objData, DragDropEffects effectsAllowed, SourceInfo info)
 at Libronix.Utility.Windows.DragDropSource.StartDrag(DependencyObject d, SourceInfo info)
 at Libronix.Utility.Windows.DragDropSource.DragDropSource_PreviewMouseMove(Object sender, MouseEventArgs e)
 at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
 at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
 at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
 at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
 at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
 at System.Windows.ContentElement.RaiseTrustedEvent(RoutedEventArgs args)
 at System.Windows.Input.InputManager.ProcessStagingArea()
 at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
 at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
 at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
 at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
 at System.Windows.Interop.HwndSource.InputFilterMessage(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 LDLS4.OurApp.InitializeAndRun(ReadOnlyCollection`1 listArgs, SingleInstanceManager sim)
 at LDLS4.OurApp.Main(String[] astrArgs)

2816.Logos.log