Yes, I mean while plying a mission!
So, now I am unsure and i will try again to delete these "userdefinied" markers.
By the way, my idea is, that my script gets the position of the markers and so i am able to give commands, where AI-units (which are not in my group) have to move to.
I want to delete this marker, when they have reached their new position (maybe for to set an new marker).
And you are sure, that i can delete them, simply by pressing "DEL" ?
I must be stupid, that it was not functioned before.