sjl/learnvimscriptthehardway — pull request #67 by jfmercer (2014-02-01 18:43:53+00:00)
Title: ESC remap has bizarre unexpected consequences; cf. http://goo.gl/0ueM5t

Remapping the key not only creates garbage output with you hit , it also disables the function keys and creates all kinds of unintended behavior. Cf. this Stackoverflow answer for a fuller explanation: http://goo.gl/0ueM5t.