* an undo chain attached; so, in particular, the cut buffer
* shouldn't be one. Sort that out.
*
- * - Reverse search.
- * + need to construct a reverse DFA.
- * + probably should construct both every time, so that you can
- * search forward for a thing and then immediately change
- * your mind and search backward for the same thing.
- *
* - In-place editing.
* + this is an extra option when running in Fix mode. It
* causes a change of semantics when saving: instead of