Can't open tpm MainPage.xaml 😕

[Lamparter]

That's so strange... I can't open Rebound.TrustedPlatform.Views.MainPage in Visual Studio....

An error occurred while initializing the frame's content
System.Runtime.InteropServices.COMException (0x8000FFFF): Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at Microsoft.VisualStudio.Platform.WindowManagement.Rdt.FindOrRegisterAndLockDocument(RdtFlags flags, String moniker, IVsHierarchy hier, UInt32 itemID, IntPtr punkDocData, RdtLock& rdtLock)
   at Microsoft.VisualStudio.Platform.WindowManagement.DocumentObjectSite.RegisterAndLockDocData()
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at Microsoft.VisualStudio.ErrorHandler.ThrowOnFailure(Int32 hr, Int32[] expectedHRFailure)
   at Microsoft.VisualStudio.Platform.WindowManagement.WindowFrame.set_DocumentSite(DocumentObjectSite value)
   at Microsoft.VisualStudio.Platform.WindowManagement.WindowFrame.InitializeDocumentSite(Boolean creatingStubFrame, Boolean replacingStubView, Object punkView, Object punkData, IServiceProvider pServiceProvider, IVsUIHierarchy pUIHierarchy, UInt32 vsid)
   at Microsoft.VisualStudio.Platform.WindowManagement.WindowManagerService.CreateContentPane(FrameMoniker frameMoniker, Boolean isDocument, String lpstrMkDoc, UInt32 eCreateWindowFlags, Object punkView, Object punkData, IServiceProvider pServiceProvider, IVsUIHierarchy pUIHierarchy, UInt32 vsid, Guid rguidCmdUI, ViewGroup parent, IVsWindowFrame& ppWindowFrame)

[Lamparter]

Ah, it's because of this character: 

                <NavigationViewItem Content="TPM Management on Local Computer" IsSelected="True">
                    <NavigationViewItem.Icon>
                        <FontIcon Glyph="" />
                    </NavigationViewItem.Icon>
                </NavigationViewItem>