Active MDT's show as inactive in Planning Area screen

Experts,

I am having issues activating a planning area when I try to add a custom master data type.

The MDT and all associated attributes are showing as active in the master data type screens (see attached screen shot 1), but when I try to enable these MDTs for a planning area in the planning area and details section, the subordinate attributes of the MDT now shown as inactive (see attached screen shot 2).

Has anyone seen this before, and if so, any ideas as to a fix/workaround?

Thanks for any responses,

Sean