Regarding ios9 system,when you turn on the portrait orientation lock, the dummy buttons of assistive touch--device--rotate screen--left&right will lose their functions.Only by turning off the portrait orientation lock,the functions can be achieved.
Obviously it is a logistic mistake during programming.when you turn off the portrait orientation lock,the gravity response system will rotate screen automatically,there is no need to do it manually.In previous systems of ios6,7 and 8,the functions of the assistive touch--device--rotate screen--left&right can be always achieved even if you turn on the portrait orientation lock.I think it should also be the original intention of the designer.
But now the designer of ios9 must misunderstand the meaning of these dummy buttons' existing,which brings much trouble to the users.
Hope apple will improve the ios9 system for this bug as soon as possible.
Dong Yu ,one of the Chinese Apple fans