Upstream bug report: https://secure.phabricator.com/T11909
On E66, I clicked "edit event". When asked, I selected "Edit all Future Events". I changed the description.
- Future events have the new title and description
- Past events keep their title and description
(It would be even better to have an option when changing the "base" event to only change "ghost" instances that have not been individually edited yet)
- All instances of E66, past and future, had their description and title overwritten. Description of old instances are apparently LOST.
- Old titles are visible in the log and can be restored manually. Conversations on past events are still there.