Todo:
- Keyboard shortcuts for resolving differences.
- How to handle tabs?
- Colourise file name.
- Bulk indent/dedent.
- Search.
- Search and replace.
- Large pastes.


Done:
- Try real unicode arrows instead of > <.
- Name it.
- Make a USAGE.
- Syntax check the cmdline.
- Make a setup.py.
- Add key to toggle sub-highlights within modification highlights.
- Fix scroll limit.
- Add key to jump to next change. Ctrl-d
- Optimize highlighting in Editor.
- Let document be saved.
- Show an indicator when the document has unsaved changes.
- Fix spaces at end of lines not being a document change.
- Correctly set cursor position when switching editors.
- Correctly optimize highlight_modification.
- Add key to cycle syntax highlighting themes (including none).
- Make changing highlighting themes work in Editor.
- Follow the cursor when moving off the screen to the left or right.
- Fix coast scrolling.
- Put it on github.
- tab key should align code.
- Right align the left editor.
- Overwrite mode.


Shelved:
- Disable ctrl-shift-h mode.
  + This mode is only in kitty.