Highlights on CotEditor 4.0

Brand-new user interface for the Big Sur era
CotEditor now has a new look. The document window, icons, and until details were delicately re-designed to be suitable for macOS 11 Big Sur.
Ready for Apple silicon
CotEditor 4.0 is a universal binary and runs natively on both Apple silicon and Intel-based Mac computers.

What's New on CotEditor 4.0.0


cf. No changes from 4.0.0-rc.

New Features

  • Brand-new user interface designed to fit macOS 11 Big Sur.
    • Update the application icon.
    • Redesign the document window.
  • Support Apple Silicon.
  • Add syntax styles for Pascal (Thanks to cbnbg!), Dockerfile, and VHDL.


  • Change the system requirement to macOS 10.15 Catalina and later.
  • Move line endings/file encoding menus from the toolbar to the status bar.
  • Change default settings of items to display in the toolbar/status bar.
  • Change the default theme from Dendrobates to Anura.
  • Change the UI of the Unicode code point input to display the input field just above the insertion point.
  • Change the “trim trailing whitespace on save” option in the General pane to perform the trimming not on save but while typing with delay, and move the option to the Edit pane.
  • On sorting lines by pattern, evaluate numbers more intelligently when the “treat numbers as numeric value” option is enabled.
  • Enable toggling the editor split orientation by right-clicking the editor split button in the navigation bar.
  • Enable action to toggle editor split orientation even when no split editor is opened.
  • Remove the Integration preferences pane and move its contents to the General pane.
  • Enable “select previous/next outline item” commands even when the navigation bar is hidden.
  • Live update selection counts while moving the selection.
  • Scroll editor by swiping the line number area.
  • Reduce the priority that CotEditor implicitly becomes the default application for specific file types.
  • Previously, CotEditor scripts written in Unix scripts, such as Ruby or Python, were decoded using the user-preferred file-encoding set in the Format preferences pane for normal documents, now they are always interpreted as UTF-8.
  • Avoid showing the “edited” indicator in the close button of document windows when the document content is empty and therefore can close the window without the confirmation dialog.
  • Avoid discarding the current input when a new item is added while another item is in editing in the syntax style editor.
  • Round the corners of current line highlight.
  • Put only the filename rather than the absolute path for the relative path insertion (<<<RELATIVE-PATH>>>) when the document file itself is dropped into the editor.
  • Remove the toolbar button to toggle page guide visibility.
  • Remove feature to import legacy syntax style definition files of which format was used in CotEditor 1.x.
  • trivial: Update the preferences window layout.
  • trivial: Improve tooltips of toolbar icons to reflect the current document state.
  • trivial: Optimize the line number calculation in vertical text orientation.
  • trivial: Always enable non-contiguous layout by the normal horizontal text orientation.
  • dev: Update the build environment to Xcode 12.2 (Swift 5.3, macOS 11 SDK).
  • dev: Replace DifferenceKit package with native CollectionDifference.
  • dev: Update Yams from 3.0.1 to 4.0.0.


  • Fix an issue that the hanging indent can be wrongly calculated when typing a word that requires user selection, such as Japanese.
  • trivial: Fix an issue in the sytnax style toolbar item that the menu selected blank if the current style was deleted.
  • trivial: Fix an issue that the i-beam for the combination of the vertical text orientation and a light theme cropped.

previous release notes