Hello,
I think it was already mentioned this on the Forum.
SMath matrix elements can be of different type (text, numbers, units etc.). If you display matrix with elements which consist units - there will be default units diaplayd ('m instead 'mm here) and you can not change the units inside matrix. I think that this feature is not implemented yet. As a workaround, you can just display the particular matrix element and then change the units into the desired one.
Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"