Morpho

If you create a custom unit that belongs to an existing unit type that contains
a space in the name ("Areal Mass Density", "Catalytic Activity", etc) the unit
does not subsequently get displayed as a member of that unit type in the NDTW.
Instead, when you try to select the unit again for another attribute, it is
listed as a unit in a separate unit type ("Arealmassdensity" instead of "Areal
Mass Density"). I think it's just a display issue, as the unit is listed in the
proper unit type if the DP is closed and re-opened.