Focus gives the keyboard only, reads empty while a header has it, and sits in the root listing's natural place

A write to /focus leaves a folded pane folded, as rio keeps current apart
from unhide; while a column or workspace tag has the keyboard no pane
does, so /focus reads empty and every pane's ctl says notcurrent (an
empty read also no longer answers stale staged bytes). focus, ctl and
commands now list after status, and the discovery test checks the root
as a set rather than by position.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 5 insertions, 1 deletions

diff --git a/docs/fs.md b/docs/fs.md
index c08500f1..5c06d206 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -135,7 +135,11 @@ generated from the registry, so it is always this build's own list.
 `/focus` reads the serial of the pane with the keyboard, and a serial written
 to it gives that pane the keyboard, off any column or workspace tag that had
 it -- rio's `current` written to a window's `wctl`, named once for the whole
-tree since there is one keyboard. A serial no pane has fails with `no such
+tree since there is one keyboard. While a column's or the workspace's tag has
+the keyboard no pane does: `/focus` reads empty and every pane's `ctl` says
+`notcurrent`. A write gives the keyboard and nothing else: a folded pane
+stays folded (unfold it with `Collapse` on its ctl), as rio keeps `current`
+apart from `unhide`. A serial no pane has fails with `no such
 window`; anything but a number, with `ill-formed control message`.
 
 A pane is made by **opening** `/pane/new`, and closed by Tremove on