Is there really any need to make this distinction? It seems to me
that only having the editable version would be good enough.
It could have OK, cancel and clear buttons always. If you don't
want to edit, you should simply not type in the box, and if you
accidentally do (or accidentally hit 'clear') you can always press
'cancel' to get out without damage. An 'edit' toggle button could be
added to enable the 'clear' button and typing, but it does seem
like overdoing it to me. Especially since the only way to pop up
these windows from the menu will give you the editable version
anyway; the non-editable versions only appear spontaneously
when /autoDisplayComment or /autoDisplayTags are on,
and a commented move is encountered or a game is loaded.