Traveller to Homeland
Shaykh Hisham asked his teacher Imam Muhammad رحمه الله about a resident of Kufah who adopts Baghdad his hometown and he has a house in Kufah as well, what should he do (regarding shortening of the prayer)?
Imam Muhammad replied that his own situation is the same as this person. So if this person has determined his new abode to be permanent one and has abandoned the original country then he must shorten his prayers when he travels there (i.e. original country). However in case of dual nationality he should not shorten his prayer.
 Fatawa Darululoom Monthly, Rabiul Awwal/Rabiul Akhir 1418 AH/1997 CE