  Virtual Reality (VR) has the potential to transform knowledge work. One
advantage of VR knowledge work is that it allows extending 2D displays into the
third dimension, enabling new operations, such as selecting overlapping objects
or displaying additional layers of information. On the other hand, mobile
knowledge workers often work on established mobile devices, such as tablets,
limiting interaction with those devices to a small input space. This challenge
of a constrained input space is intensified in situations when VR knowledge
work is situated in cramped environments, such as airplanes and touchdown
spaces.
  In this paper, we investigate the feasibility of interacting jointly between
an immersive VR head-mounted display and a tablet within the context of
knowledge work. Specifically, we 1) design, implement and study how to interact
with information that reaches beyond a single physical touchscreen in VR; 2)
design and evaluate a set of interaction concepts; and 3) build example
applications and gather user feedback on those applications.
