[Groff] PIC: access global labels from within a [] block

[Vasily Ponomarev]

Hello everybody.

Inside a picture environment I have a box with a label "GLOBAL".
Then a I want to position another box inside a block with respect to the
global box:

.PS

GLOBAL: box "Global"

[
   box "Local" at GLOBAL.s.x, GLOBAL.s.y + 1
]


.PE

It is not working.
Any idea why?

Thanks in advance.
Best regards,
Vasily.