fallback fonts? remote display - xlib

[Riccardo Mottola]

Hi,

I launch an app on my Raspberry with xlib and remote display.

2020-06-16 10:40:33.831 ProjectCenter[29598:29598] No font cache 
available - building new one - this may take several seconds (or minutes 
on a slow machine with lots of fonts)
2020-06-16 10:40:33.834 ProjectCenter[29598:29598] Running 
/GNUstep/System/Tools/font_cacher
2020-06-16 10:42:03.487 ProjectCenter[29598:29598] XGFont: selected 
font: Helvetica at 12.000000 ((null)) is not available.
2020-06-16 10:42:03.488 ProjectCenter[29598:29598] The font specified 
for NSFont, Helvetica, can't be found.
2020-06-16 10:42:03.488 ProjectCenter[29598:29598] XGFont: selected 
font: Helvetica at 12.000000 ((null)) is not available.
2020-06-16 10:42:03.489 ProjectCenter[29598:29598] XGFont: selected 
font: Helvetica at 12.000000 ((null)) is not available.
2020-06-16 10:42:03.489 ProjectCenter[29598:29598] XGFont: selected 
font: Helvetica at 12.000000 ((null)) is not available.
2020-06-16 10:42:03.490 ProjectCenter[29598:29598] XGFont: selected 
font: Courier at 12.000000 ((null)) is not available.
2020-06-16 10:42:03.491 ProjectCenter[29598:29598] XGFont: selected 
font: Fixed at 12.000000 ((null)) is not available.

<<...>>

2020-06-16 10:42:04.267 ProjectCenter[29598:29598] NSFont.m:1513 
Assertion failed in GSCInlineString(instance), method initWithCoder:. 
Couldn't find a valid font when decoding.
2020-06-16 10:42:04.270 ProjectCenter[29598:29598] Exception occurred 
while loading model: NSFont.m:1513  Assertion failed in 
GSCInlineString(instance), method initWithCoder:.  Couldn't find a valid 
font when decoding.
2020-06-16 10:42:04.272 ProjectCenter[29598:29598] Failed to load Gorm

<<...>>

2020-06-16 10:42:04.342 ProjectCenter[29598:29598] XGFont: selected 
font: Fixed at 12.000000 ((null)) is not available.
Segmentation fault

now.. I wonder why? I launched "xfontsel" on the raspberry.
Am I right to assume that the fonts seen there are the one availbale to 
the backend too?

I see Helvetica, e.g.:

-*-helvetica-*-r-*-*-12-*-*-*-*-*-*-*

-*-courier-*-r-*-*-12-*-*-*-*-*-*-*

what am I missing?

Riccardo