Method GetCurrentActivePosition

src/newgrf_gui.cpp:677–684

	}

	int GetCurrentActivePosition() const
	{
		if (this->active_sel != nullptr) {
			auto it = std::ranges::find_if(this->actives, [this](const auto &c) { return c.get() == this->active_sel; });
			if (it != std::end(this->actives)) return static_cast<int>(std::distance(std::begin(this->actives), it));
		}
		return -1;
	}

	/**
	 * Test whether the currently active set of NewGRFs can be upgraded with the available NewGRFs.