I originally picked "under" as the preposition to go before
a platform name, but obviously you should build "on" a
platform, and "under" suddenly annoys me. The choice of "on"
is now codified in the documentation style guide. Meanwhile,
"Unix" insted of "X" seems more clear and consistent in the
`racket/gui' docs.
More usefully, this patch also fixes a few out-of-date
platform-specific claims.
- improved the drawing speed in mrlib's graph pasteboard
by caching the background arrows (optionally; only turned
on for the module browser. in redex, this probably won't
speed anything up so it isn't used)
- added a search feature to the module graph to help find
dependencies; type in string and some of the graph changes
color
