If you can test more, have a look
at the NEWS file or the one on the webpage
http://www.gnu.org/software/xboard/whats_new/4.6.0/
and check out the new features :)
I want to point out that for testing it can be very important to
delete (or move) your settings file ~/.xboardrc , to make sure
that the settings we now distribute with will not be masked
by your settings from previous versions!
Also note that a new feature not mentioned in the above file
is the internationalization: people are encouraged to test if
the various national versions do work, and do not upset
formattig of dialog layouts.
