am 1986ed7a: am 86141f6d: am 3d6b094b: am d76f80bd: Merge "ignore null TaskStack and continue layout for PRIVATE_PRESENTATION window" into lmp-dev

* commit '1986ed7a9b9832be1c40551c4a5c588a979a85a2':
  ignore null TaskStack and continue layout for PRIVATE_PRESENTATION window