When opening brackets 1.0.0-15191 in Windows 8 I get this error caused by the csscomb extension:
Unable to parse key binding Cmd-alt-c. Permitted modifiers: Ctrl, Cmd, Alt, Opt, Shift; separated by '-' (not '+').
Commenting-out line 60 of the file /extensions/user/csscomb-brackets/main.js fixes this issue.