ok, I think this should be possible.
Will look into it later.
here is an example now, how you can select values for a MIGX-item from another grid:
https://github.com/Bruno17/migxselectfromgrid
Hi Bruno17.
I have a problem with your solution after migx update. Can you help me to fix my config?
your custom grid - configs are allready included automatically, when you put them under
components/yourpackage/migxconfigs/grid/grid.config.inc.php
Thanks alot. Migx is most useful package i used but it have one significant deficiency. There is no comprehensive manual. I think it because you dont have enough time for it. May I offer you some help in creating a more informative MIGX guide?