How do you cast a struct to a derived struct?

Development Programming & Scripting
1

I always want to show the mouse cursor, when I am in UIOnly or GameAndUI InputMode. So I thought I would be clever and would override SetInputMode() in my PlayerController class:

void ABasePlayerController::SetInputMode(const FInputModeDataBase & InData)
{
	Super::SetInputMode(InData);
	const FInputModeDataBase* InDataPtr = &InData;
	const bool bIsGameOnlyInput = static_cast<const FInputModeGameOnly*>(InDataPtr) != NULL;
	bShowMouseCursor = bIsGameOnlyInput ? false : true; // Always show the mouse, when in UI Mode
}

Fortunately the code is compiling, but unfortunately the code is not working. When I log out bIsGameOnlyInput, it is always true, even though I am clearly in GameAndUI InputMode, because I can interact with my UI and I can control my Pawn.

Do You have any ideas, how else I can check whether the “const FInputModeDataBase & InData” parameter is of type FInputModeGameOnly?