Can someone help?

Used to work fine. Only system change I can think of is moving to 4K display. Tried setting the desktop to 1920x1080 but no good.

The log file is pretty blank.

Windows (.NET) error log is as follows:

Application: Plan-G3.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ArithmeticException

Exception Info: System.OverflowException
   at System.Windows.Media.Imaging.ColorConvertedBitmap.FinalizeCreation()
   at System.Windows.Media.Imaging.ColorConvertedBitmap..ctor(System.Windows.Media.Imaging.BitmapSource, System.Windows.Media.ColorContext, System.Windows.Media.ColorContext, System.Windows.Media.PixelFormat)
   at System.Windows.Media.Imaging.BitmapImage.FinalizeCreation()
   at System.Windows.Media.Imaging.BitmapImage.EndInit()
   at System.Windows.Media.Imaging.BitmapImage..ctor(System.Uri, System.Net.Cache.RequestCachePolicy)
   at Plan_G3.MarkerImages.VRP_UC..ctor(Plan_G3.Map, GMap.NET.WindowsPresentation.GMapMarker, Plan_G3.MarkerImages.MkrWayppointType, System.String)
   at Plan_G3.ViewModel.MainViewModel.DisplayUWptMarkers(Double, Double, Double, Double)
   at Plan_G3.ViewModel.MainViewModel.updateMarkers()
   at Plan_G3.MainWindow.MainMap_OnCurrentPositionChanged(GMap.NET.PointLatLng)
   at GMap.NET.Internals.Core.set_Position(GMap.NET.PointLatLng)
   at Plan_G3.ViewModel.MainViewModel.MoveMapToCurrentPosition()
   at Plan_G3.ViewModel.MainViewModel.StartMap()
   at Plan_G3.MainWindow.dispatcherTimer_Tick(System.Object, System.EventArgs)
   at System.Windows.Threading.DispatcherTimer.FireTick(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.DispatcherOperation.InvokeImpl()
   at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(System.Object)
   at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at MS.Internal.CulturePreservingExecutionContext.Run(MS.Internal.CulturePreservingExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Windows.Threading.DispatcherOperation.Invoke()
   at System.Windows.Threading.Dispatcher.ProcessQueue()
   at System.Windows.Threading.Dispatcher.WndProcHook(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.DispatchMessage(System.Windows.Interop.MSG ByRef)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame)
   at System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame)
   at System.Windows.Application.RunDispatcher(System.Object)
   at System.Windows.Application.RunInternal(System.Windows.Window)
   at System.Windows.Application.Run(System.Windows.Window)
   at Plan_G3._Main.Main()

First of all, let me say this is one amazing piece of software. I can't believe I only now stumbled upon it and even that by accident.

Quick question/suggestion. and I apologize if this was covered before:
- I like to build my plans by setting the departure and arrival airports and then fill in the waypoints in between. I was wondering if it was possible to lock the arrival (destination) airport as the last waypoint in the plan so I don't have to 'move up' every waypoint that I add through a right click on the map (they become the last waypoint in the plan). Alternatively, if a right click waypoint could be inserted after the selected waypoint in the plan, that would also be OK.

Amit