Can't edit default UPROPERTIES in my GameMode?

Hi, I have a gamemode in C++, with three pointers to Generators (which are Actor subclasses).

// Copyright 1998-2016 Epic Games, Inc. All Rights Reserved.
#pragma once
#include "GameFramework/GameMode.h"
#include "Generator.h"
#include "HShooterGameMode.generated.h"

UCLASS(minimalapi)
class AHShooterGameMode : public AGameMode
{
	GENERATED_BODY()

public:
	AHShooterGameMode();

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Gameplay)
	AGenerator* A;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Gameplay)
	AGenerator* B;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Gameplay)
	AGenerator* C;
};

I have a blueprint child of this gamemode, and I want to set the defaults for A, B, and C through that child and use that as my gamemode in the level, however it won’t let me select them.

The drop down menu shows the actors I want to assign to A,B, and C, but when I click on them, nothing happens. The menu disappears.

What is the problem here?

In BPs you can’t point to objects that are put into your level, since BPs are classes that will have to work on their own, regardless of what level they are in! What you could do is to spawn your AGenerators in your GameMode class.