Re: [O] Buffer is read-only: #<buffer *SUMO*>

[Aaron Ecay]

OK, I’ve tracked this down.  I added a function to
‘org-agenda-finalize-hook’ which makes modifications to the agenda
buffer (viz. removing the 'mouse-highlight text properties).  At line
3441 of org-agenda.el, in the ‘org-agenda-finalize’ function, this hook
is run outside of any (let ((inhibit-read-only t)) ...).  This gives the
error.

Only some types of agenda buffers are set to be read-only –
e.g. ‘org-todo-list’ sets read-only at l. 4418 of org-agenda.el.  I
think ‘org-agenda-finalize-hook’ should be run with inhibit-read-only
bound to t, to let the hook modify the agenda buffer in any case.  But
otherwise, it should be added to the hook’s documentation that any
changes to the agenda buffer could be turned into an error by a
read-only setting.

-- 
Aaron Ecay