[NTG-context] disabling font features with xetex (was: Monospaced greek font)

12 Sep 2009

      On Tue, 8 Sep 2009, Wolfgang Schuster wrote:
...
Am 08.09.2009 um 06:56 schrieb Aditya Mahajan:
...
Hi,
Is there a monospaced font which matches with Latin Modern and contains 
greek letters?
Computer Modern Unicode Sans Serif
How do I remove font features with xetex? I have the following example, 
with cmuntt taken from 
ftp://canopus.iacp.dvo.ru/pub/Font/cm_unicode/cm-unicode-0.6.3a-otf.tar.gz

\starttypescript [mono] [cmunicode]
      %\setups[font:fallback:mono]
      \definefontsynonym [Mono]           [file:cmuntt]
                         [features=none]
      \definefontsynonym [MonoItalic]     [file:cmuntt]
                         [features=none]
      \definefontsynonym [MonoBold]       [file:cmuntt]
                         [features=none]
      \definefontsynonym [MonoBoldItalic] [file:cmuntt]
                         [features=none]
\stoptypescript

\definetypeface[mainface][rm][serif][modern]   [default]
\definetypeface[mainface][ss][sans] [modern]   [default]
\definetypeface[mainface][tt][mono][cmunicode] [default]
\definetypeface[mainface][mm][math][modern] [default]

\setupbodyfont[mainface,10pt]

\starttext
\type{suffix} \type{αβγ}
\stoptext

With luatex it works fine, but with xetex I get the ffi ligature in 
"suffix". Any idea how to get rid of it in xetex?

Thanks,
Aditya