#ifdef and #ifndef have no affect in header files

#ifdef and #ifndef have no affect when used in the header file of a class.

Ex:

#ifndef MYMACRO
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Test)
		float ANumber;
#endif

ANumber variable does not show up in the editor when MYMACRO is not defined. Inverse also does not appear in editor (using #ifdef with macro defined)

1. Open UE4 Editor
2. Add code to project based on Actor (MyActor)
3. In MyActor.h add the following:

   #ifndef RANDO
   	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Test)
   		float ANumber;
   #endif
   

4. Compile
5. Create blueprint based on MyActor (MyActorBP)
6. Add instance of MyActorBP to the level

Result:
ANumber does not appear in the details panel for the MyActorBP instance

Expected:
Since

#ifndef not working