[Oberon] PO2013 - System.CloseTrack / System.ExtendDisplay

[Andreas Pirklbauer]

   > can anyone explain me how the *commands* System.CloseTrack
   > and System.ExtendDisplay are supposed to be used?

System.CloseTrack with a viewer selected does the same
as System.Close *after* the user has executed System.Grow
on that viewer: it closes the overlaying track created by
System.Grow and restores the one below it.

System.ExtendDisplay was implemented on Ceres to use
multiple physical monitors attached to the same computer.
It is not implemented in FPGA Oberon (one would need to
add memory for another frame buffer).