How to select an actor in-game using GetHitProxy?

This is the stack trace of the crash on Visual Studio:


 	KernelBase.dll!00007ffc2bab77d2()	Unknown
>	UE4Editor-D3D11RHI.dll!FD3D11DynamicRHI::RHISetViewport(unsigned int MinX, unsigned int MinY, float MinZ, unsigned int MaxX, unsigned int MaxY, float MaxZ) Line 220	C++
 	UE4Editor-RHI.dll!SetViewport_Internal(unsigned int MinX, unsigned int MinY, float MinZ, unsigned int MaxX, unsigned int MaxY, float MaxZ) Line 1521	C++
 	UE4Editor-Engine.dll!`FCanvas::Flush_GameThread'::`18'::EURCMacro_CanvasFlushSetupCommand::DoTask(ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 871	C++
 	UE4Editor-Engine.dll!TGraphTask<`FCanvas::Flush_GameThread'::`18'::EURCMacro_CanvasFlushSetupCommand>::ExecuteTask(TArray<FBaseGraphTask *,FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 669	C++
 	UE4Editor-Core.dll!FTaskThread::ProcessTasks(int QueueIndex, bool bAllowStall) Line 428	C++
 	UE4Editor-Core.dll!FTaskThread::ProcessTasksUntilQuit(int QueueIndex) Line 271	C++
 	UE4Editor-RenderCore.dll!RenderingThreadMain(FEvent * TaskGraphBoundSyncEvent) Line 282	C++
 	UE4Editor-RenderCore.dll!FRenderingThread::Run() Line 404	C++
 	UE4Editor-Core.dll!FRunnableThreadWin::Run() Line 73	C++
 	UE4Editor-Core.dll!FRunnableThreadWin::GuardedRun() Line 48	C++
 	[External Code]


Anyone from Epic can help me on this? Because I can’t find any code snippet about how to use GetHitProxy() in-game. Thank you.