[[template id=plugin name=editdiff author="[[JeremieKoenig]]"]]
[[tag type/useful]]

This plugin adds a "Diff" button when a page is being edited.
When clicked, a diff between the stored page and provided content
is shown in the "Page Preview" area.

## Problems

No special handling is done of concurrent edits: changes introduced
independently will show up in the requested diff, although they will
be merged when the page is saved. I suspect even detecting this case
would require changes in the RCS backends.
