Materials don`t work properly in control box or disappear

I´ve a problem
with flamingo nxt materials.

For example:
I place an existing nxt-material in the control box, copy it, change the properties and
change the material´s name as well. The result could be that there are no
changes at all. When I delete the new created material (because it doesn´t
work) the first material will be deleted instead! It also happened to me that
new created materials after several renderings didn´t work anymore.

Does this happens also to other members, or is there a handling problem from my side.

I´m using windows
7 /64 bit, Rhino5, flamingo nxt, actual servicepack.