Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Reproduced the problem in Safe Mode: http://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
  • Followed all applicable steps in the debugging guide: http://flight-manual.atom.io/hacking-atom/sections/debugging/
  • Checked the FAQs on the message board for common solutions: https://discuss.atom.io/c/faq
  • Checked that your issue isn't already filed: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aatom
  • Checked that there is not already an Atom package that provides the described functionality: https://atom.io/packages

Description

Shortcuts with alt don't suppress Mac OS composition characters.

Steps to Reproduce

With ABC - Extended keyboard layout:

1. Open Your Keymap
2. Add the following keymaps:

# general
'atom-text-editor':
  # use jkl; vim-like when pressing alt (word by word, paragraph by paragraph)
  # or alt (letter by letter)
  'alt-h': 'core:move-left'
  'alt-j': 'core:move-down'
  'alt-k': 'core:move-up'
  'alt-l': 'core:move-right'

3. save
4. try to use them

With US keyboard layout /cc #15189 (comment).

Expected behavior: [What you expect to happen]

A GIF from atom-1.18

Actual behavior: [What actually happens]

A GIF from atom-1.19

Reproduces how often: [What percentage of the time does it reproduce?]

Always.

Versions

• Atom: 1.19.0-beta7
• Atom-Shell:
• OS: Mac OS X 10.12.5
• Misc
  • apm 1.18.2
  • npm 3.10.10
  • node 6.9.5 x64
  • python 2.7.10
  • git 2.11.0

Additional Information

Probably only happens on Mac OS.