Hello all,

With the latest 6.0 beta image and a from-git `Cog` branch VM freshly 
compiled on Debian x86_64, I see the following:

squeak -- -evaluate '[Preferences setDemoFonts] valueSupplyingAnswer: true'

--> correctly evaluates, answers `Preferences`

squeak -vm-display-null -- -evaluate '[Preferences setDemoFonts] 
valueSupplyingAnswer: true'

--> fails, with `Error: primitiveWindow:width:height: failed`

This didn't used to happen! Has something changed wrt vm-display-null?

Cheers,
   Tony