What is the ruling on performing Tarawih prayer in congregation immediately after the 'Isha prayer, and performing Qiyam al-Layl before Fajr? Is it obligatory to suffice with one, or is it permissible to add more?

It is permissible for someone who has prayed Tarawih to perform Qiyam al-Layl or Tahajjud afterwards, and he should delay his Witr prayer to be the last of his prayers at night. As for someone who prayed Tarawih with the Imam and performed Witr, and then wishes to perform Qiyam al-Layl, he should not repeat Witr, based on the Prophet's (peace be upon him) saying: "There are not two Witr prayers in one night."