Highlights on CotEditor 3.0

Swift migration
All of source codes for CotEditor was completely rewritten in Swift from Objective-C.
Tabbed window
Finally, CotEditor now supports tabbing windows on Sierra. On CotEditor 3.0, the tab behavior was improved from the standard Sierra implementation in order to let it behave more naturally.
Brushed-up look
Graphic images like toolbar icons and application icon were also updated to get more modern look.
New text search engine
The find panel's regular expression engine was changed from Onigmo (Oniguruma-mod) to the ICU library. Thanks to that, the line-up of text search is updated with new useful items and not only for the regex search but also for the normal texture search.
Support macOS Sierra
Hello to Sierra and good-bye to Mountain Lion and Mavericks. So, CotEditor now supports from OS X 10.10 to macOS 10.12.

What's New on CotEditor 3.0.0


cf. Changes from 3.0.0-rc.2.

New Features

  • Support window tabbing on macOS Sierra:
    • Add “New Tab” action to File menu.
    • Sync sidebar visibility among tabs in a window.
  • Display recent used syntax styles at the top of the toolbar syntax style popup list.
  • Add individual “Block Comment”, “Inline Comment” and “Uncomment” actions in Text menu unlike the “Comment Selection” action changes its behavior intelligently.
  • Add Italian localization (thanks to Agostino Maiello!).


  • Support macOS 10.12 Sierra and drop support for OS X 10.8 Mountain Lion and 10.9 Mavericks.
  • Migrate all source code from Objective-C to Swift.
  • Update application icon.
  • Update find panel search algorithm:
    • Change the regular expression engine from Onigmo to the ICU library.
      • From this, the reference symbol of matches is changed from \1 style to $1.
    • Update line-up of the advanced search options.
  • Enable Autosave and Versions by default.
  • Inserting single surrogate character is no more valid.
  • Update toolbar.
  • Update preferences icons.
  • Exclude file extension from the initial selection in document save panel.
  • Update key binding setting format.
    • Not compatible with previous key bindings setting. Please customize again in the preferences window.
  • Auto-sync Script menu with script folder.
    • Now, you don't need anymore to update script menu after script folder modification.
  • New acknowledgements window.
  • Update “Swift” syntax style to Swift 3.0.
  • Update “Coffee Script” syntax style for the block regular expression.
  • Improve syntax highlighting algorithm with symbols.
  • New “Go To Line” panel.
  • Display “Not Found” in the find string field in the find panel also when “Find All” failed.
  • Remove the following less important text actions:
    • Insert Encoding Name with “charset=”
    • Insert Encoding Name with “encoding=”
  • Remove the following less important toolbar items:
    • Show / Hide Navigation Bar
    • Show / Hide Line Numbers
    • Show / Hide Status Bar
  • Remove the feature that changes the line height of current document from the “Format” menu.
    • From this, line spacing property on AppleScript is also deprecated.
  • Remove “Not writable” alert which displayed on file opening.
  • Remove “Set as Default” button in the editor opacity panel.
  • Change specification not to treat full-width spaces as indent.
  • Add help buttons to syntax style editor.
  • Make text font, theme and tab width restorable from the last session.
  • Make indent deletion more naturally.
  • Remove byte count display in document inspector.
  • Display also an accurate file size in document inspector.
  • Display dialogs for changing file encoding as a document-modal sheet.
  • Move scripting manual into help contents.
  • Make window size setting window translucent.
  • Avoid expanding status bar into side inspector.
  • Improve line height calculation.
  • Keep visible area after toggling text-wrapping.
  • Improve scrolling with line number view drag.
  • Better syntax highlighting while editing.
  • Enable activate “Show Invisibles” action even if all of invisible characters were set as not shown when the document was opened.


  • Fix an issue find string is not shared with other applications after quitting CotEditor.
  • Fix an issue where some of script APIs returned always string with LF line endings.
  • Fix an issue where page guide remained after toggling page guide visibility.
  • Address an issue with drawing area of zoomed character view in character inspector popover.

previous release notes