Custom measurements 
Using this button, you can make custom measurements you have
set in the library (See General/Library/Custom Measurements). Click the
button and a list of the
available custom measurements of the library appears. By selecting one of them,
the following window appears:
The
‘Measurement details’ region’s exact form depends on whether the custom
measurement is of object, length, area or volume type.
Description/Category /Color/Notes/Factor