Scenario:
* start out with some text on screen
* select some text A, delete
* select some more text B, delete
* press C-z twice to restore A and B
* press C-y twice
Before this commit only the first C-y was having an effect (deleting B).
The second was failing to delete A.
I see a path to at least maintain a single fragment per screen line. But
can we do better? It even seems unnecessary to maintain two copies of
the data, chopped up into lines and screen lines.
It's just uneconomic to maintain given how little I've used it. I have a
bug right now and no time to port the bugfix to all the complexities of
the B side.
I briefly considered tossing out the entire source editor. But I _have_
been using it to browse logs across sessions. The live editor doesn't
quite cover all my use cases just yet.
We now have duplication in the source editor only for:
* syntax highlighting
* hyperlinking [[WikiWords]]
* ability to hide cursor (when showing file browser or Focus is in log browser)
scenario:
press ctrl+f, type in a string
hit down arrow if needed until the screen scrolls
press enter
click with the mouse somewhere
Before this commit the app would crash because cursor was above screen
top.
Scenario: make some edits, select some text, make some more edits. Press
ctrl-z.
Before this commit, undo would stop at the point of selection and
previous edits would become unreachable.
After this commit, both ctrl-z and ctrl-y seem able to span the point of
selection.
I've been running out of ctrl+ shortcuts, and I just remembered my
original idea to keep ctrl+ for drawings/mouse operations and alt+ for
everything else.