makin open source-code is a bit like publishing a scientific article,
others papers cannot (or should not) copy 1:1 but the idea can be
used.
But that in part of the game, as well as debate of the features
(including user interfaces ;^)

At 19:36 10 January 2013, Tobias Bieniek wrote:
I believe that these open source SW project have caused major
improvement to the gliding SW in general. The commercial SW
developers are surely following the development intensively,
and copying the best parts into their product.

Well let's hope they are not just copying them without having a look
at the
license... XCSoar (and LK8000) are free and open-source, but
under a
license that only allows others to use the source code if their
software
will be free and open-source too.