Offering the Tarawih behind the Imam and delaying the Witr to be offered before sleeping

Q 2: All praise be to Allah that I offer the Tarawih Prayers behind the Imam, but it is my habit that I offer the Witr Prayer before I go to bed even while traveling. I offer all the Rak`ahs (units) of Prayer behind the Imam except for the Witr Prayer which I offer before sleeping. Which was better according to the Salaf (righteous predecessors); offering all the Rak`ahs of the Tarawih Prayers and the Witr Prayer including the supplication behind the Imam or offering the Rak`ahs of the Tarawih Prayers behind the Imam and offering the Witr Prayer alone before sleeping? If offering the Tarawih Prayers until supplication is better, how can I offer some optional prayers before sleeping? Should I offer Shaf` Prayer? Or Should I offer Witr Prayer? Or is there no Prayer to be performed after offering the Witr Prayer behind the Imam? (Part No. 6; Page No. 92

A: It is better to offer the Tarawih Prayers and the Witr Prayer behind the Imam, as the Prophet (peace be upon him) said: If a man prays with an Imam until he leaves, he is reckoned as having spent a whole night in prayer. If you want to offer some optional prayers at night before sleeping, you can offer whatever prayers you want, but you should not offer the Witr Prayer again as you have already offered it behind the Imam.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.