How do you change the Modelsim Cursor Resolution (not simulation resolution)

[Andrew FPGA]

Sigh.

Does anyone know how to change the time resolution displayed by the
cursor in modelsim. e.g. my simulation resolution is ps, and I want to
use the cursors to measure the amount of time between two particular
cursor locations. Modelsim gives me a value in ps. My brain would
prefer to see a number in ns for example.

Tried setting UserTimeUnit = ns in *.mpf but that seems to have no
effect.

Regards
Andrew