We include the CodeMirror JS Editor in PyLucid with commit c7f6ea0
You will see the the "In-browser code editor" if you change "Editable html head files" or "dbtemplates".
You will get Syntaxhighliging and you can now Indent with TAB and Shift-TAB !
PyLucid users: You must update the PyLucid media files, if you copied and not symlink them, see: Backwards-incompatible changes