Blimey! Neat!!! I found the answer myself... Look what I found in Samayatree's post - Canonicity and Divine Interference: The Tulkus and the Shugden-Controversy:-
Phabongkhapa: This sectarian emphasis or exclusivity is evident in Phabongkhapa (1878-1941). Phabongkhapa (pha bong kha pa byams pa bstan 'dzin phrin las rgya mtsho) is a key figure in the history of the Shugden controversy. He was a charismatic teacher and member of the Sera Me monastery. Whether he received the Shugden tradition and the controversial Sogde (srog gtad, i.e. life-entrustment) from his teacher Tagphu or not, he preached it forcefully, initiated many disciples into it, and made this practice popular among high Gelukpa Lamas. In his 'Initiation texts for the practice of the visionary teachings' which he had received from Losang Choekyi Wangchuk (blo bzang chos kyi dbang phyug), there are teachings on Amitayus, Avalokiteshvara, Vajrapani, Tara and the Guru Yoga, and there is no mention of Shugden because the text deals with high Tantric initiations. That Shugden is not mentioned in this context suggests that he considers the deity not among this high class of deities. However, in his text 'The profound blessing of life-initiation of Shugden, the most powerful dharmapala of Jamgön (Tsongkhapa), the jewel chariot bringing forth a mass of blessings' he gives a detailed account of the Shugden practice and remarks—
" I have written this at the request of Shugden, because in the past there was a tradition of Sogde (srog gtad) to Shugden but later neither the tradition nor the text could be found—they have become like flowers in the sky—so Shugden has asked me two times to write a new initiation text. I have passed on the practice of initiation (dbang) to some disciples in accordance with my own experience, and (a text) has been written as a seed for (a detailed text). But only that would be not reliable and something like an illegitimate son. Therefore, I explained it in detail to my master Tagphu Dorje Chang and presented this draft to him. ... He took that draft and wrote his text down, combining this seed text with his own vision. Tagphu commented about the five types of Shugden, the respective colors etc., the offerings to be arranged, thus at the time of initiation the large Lamrim text should be there on the altar, a cakra representing one's life, damaru, dorje etc. The practitioner has to utter the life generating words of Vajrabhairava and to make torma offerings. ... The initiation can be given to somebody who has received initiation into Vajrabhairava and keeps the commitments connected with it. ... Though there are so many different traditions and philosophies in Tibet, only this tradition of Tsongkhapa is the supreme, the top of the victory banner, the most complete, the essence of the teaching. ... To bring Shugden into one's own service is a very powerful blessing. In order to receive this initiation the disciples visualize themselves as the yidam (Vajrabhairava) and as such invoke and control Shugden. The dharmapala (Shugden) is presented to the disciples as the one who abides by their commands."
