Hi there, your app looks very nice, unfortunately I'm unable to configure/use it with P3D V3.x.  I've installed version 3.1.3.113.

As soon as I click on the "Nav Database" tiny expand button to try to configure my platform of choice, I get the following error:

Log Name:      Application
Source:        .NET Runtime
Date:          5/8/2016 10:20:19 AM
Event ID:      1026
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      DESKTOP-SF99NDG
Description:
Application: Plan-G3.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.InvalidCastException
   at Plan_G3.Views.BuildOptionsDialogView.Window_Loaded(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs)
   at System.Windows.BroadcastEventHelper.BroadcastEvent(System.Windows.DependencyObject, System.Windows.RoutedEvent)
   at System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(System.Object)
   at MS.Internal.LoadedOrUnloadedOperation.DoWork()
   at System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(System.Object)
   at System.Windows.Media.MediaContext.RenderMessageHandler(System.Object)
   at System.Windows.Media.MediaContext.Resize(System.Windows.Media.ICompositionTarget)
   at System.Windows.Interop.HwndTarget.OnResize()
   at System.Windows.Interop.HwndTarget.HandleMessage(MS.Internal.Interop.WindowMessage, IntPtr, IntPtr)
   at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndWrapper.WndProc(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr, IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.HwndSubclass.DefWndProcWrapper(IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr, IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)


Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name=".NET Runtime" />
    <EventID Qualifiers="0">1026</EventID>
    <Level>2</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2016-05-08T17:20:19.221738700Z" />
    <EventRecordID>18428</EventRecordID>
    <Channel>Application</Channel>
    <Computer>DESKTOP-SF99NDG</Computer>
    <Security />
  </System>
  <EventData>
    <Data>Application: Plan-G3.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.InvalidCastException
   at Plan_G3.Views.BuildOptionsDialogView.Window_Loaded(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs)
   at System.Windows.BroadcastEventHelper.BroadcastEvent(System.Windows.DependencyObject, System.Windows.RoutedEvent)
   at System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(System.Object)
   at MS.Internal.LoadedOrUnloadedOperation.DoWork()
   at System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(System.Object)
   at System.Windows.Media.MediaContext.RenderMessageHandler(System.Object)
   at System.Windows.Media.MediaContext.Resize(System.Windows.Media.ICompositionTarget)
   at System.Windows.Interop.HwndTarget.OnResize()
   at System.Windows.Interop.HwndTarget.HandleMessage(MS.Internal.Interop.WindowMessage, IntPtr, IntPtr)
   at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndWrapper.WndProc(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr, IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.HwndSubclass.DefWndProcWrapper(IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.UnsafeNativeMethods.CallWindowProc(IntPtr, IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)

</Data>
  </EventData>
</Event>

Sorry for the long exception list, but hopefully some information in it might point you in a direction.  Any thoughts?

Cheers, Rob.