My friend shared with me the following :
The Great Lamrim master, Dagpo Dorje Chang, went into meditation, left His body and travelled to the throne / place of Maitreya buddha. In the great assembly in Maitreya palace, Dagpo Dorje Chang folded His hands and requested Tulku Drakpa Gyeltsen directly to please expound the mystical tantra, the mandala, the prayer, the lineage and the teachings about the dharma Proctector Dorje Shugden field.
In the text, Trijang Rinpoche said from the heart of Tulku Drakpa Gyeltsen, rainbow lights eminated out and hit Lama Tsongkhapa's heart. Lama Tsongkhapa from His heart again lights came out and hit Tulku Drakpa Gyeltsen's heart. Finally the last of the lights from Tulku Drakpa Gyeltsen heart went out and went under Lama Tsongkhapa's throne.
From under Lama Tsongkhapa's throne, the complete mandala for the first time ever of Dorje Shugden, the 5 families, the 32 entourage, Karche Marpo appeared directly in front of the entourage, in front of the whole assembly.
And then Dagpo Dorje Chang had a vision, He saw the whole entourage, He saw who they are, instantly He received the teachings, the lineage, oral transmission, the instructions immediately. Then the whole mandala again dissolved back under Lama Tsongkhapa's throne, to show you who’s Protector they are!