* This approach puts one top-level definition per file, and so obscures the
  order in which definitions are loaded. In particular, initializing a global
  table to contain other global definitions will fail if you originally
  authored the other global definitions after the table.
  I never initialize global tables with other definitions. That kind of thing
  happens in `on.initialize` (akin to `love.load`; see reference.md) or
  `on.code_change`.
* Don't start the driver app while multiple freewheeling apps are running. If
  you have a driver app running with one app, shut it down before you switch
  apps.

* No support yet for Unicode graphemes spanning multiple codepoints.
* No support yet for right-to-left languages.
* Can't scroll while selecting text with mouse.