* TODO [Bug] Avoid firing =before-change-functions= on every redisplay

On every redisplay the indicator is recalculated using =format-spec=
which happens to trigger =before-change-functions= despite working in
a temporary buffer.  It's unclear whether the bug is in code hooking
=before-change-functions=, =before-change-functions= considering
temporary buffers or using an function with an =:eval= spec.  Suppose
the latter, the following changes need to be done:

- Use a variable holding the mode line indicator.
- Ensure the variable is rendered correctly in the mode line (it might
  be necessary to mark it as risky variable).
- Add code to all commands modifying the indicator state to update the
  variable.

* TODO [Feature] Add commands for moving window configs in frame

The easiest way this could turn out is like in i3, with a command to
move the window config from one slot to another one.  Essentially
renaming and reordering.  The =C-M-= prefix could be used for
predefined commands.

* TODO [Feature] Add commands for moving window configs across frames

Not sure how this should be designed.  There's a few problems:

- It's hard to identify frames by a textual description, something
  like using visual indicators (like putting a colored frame or
  overlaying a big number) might fix this.
- Specifying both slot to move to and frame can be tedious.  There's a
  funny way of doing that with i3 where slots are numbered across
  frames and window configs can be moved to a slot belonging to a
  frame.

* TODO [Enhancement] Improve documentation with screencasts

Common workflows should be shown with GIFs displaying the modeline
indicator, keys and commands used.

* TODO [Enhancement] Add missing Vim Ex commands

See [[evil.org]]