A focus write makes its pane's column the active one, and layout's active is it

Writing a serial to /focus gave that pane the keyboard but left the active
column where it was, so pane/new under Placement acme went elsewhere, and
/layout's active named the keyboard's column rather than where a new pane
would go. A focus write now sets the active column as the user's click
there would, under either Placement, and /layout's active names the active
column, which pane/new and a look place into.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/docs/fs.md b/docs/fs.md
index 55660bc0..a5d3c4ca 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -102,11 +102,13 @@ Existing Plan9port/v9fs clients need a userspace bridge for QUIC.
              write follow to that open to wait for more
 /screen      rendered screen JSON; frozen per open handle
 /listeners   the session's dial addresses
-/focus       the serial of the pane with the keyboard; write a serial to give it the keyboard
+/focus       the serial of the pane with the keyboard; write a serial to give it the keyboard,
+             which makes its column the active one as a click there would
 /ctl         the settings, one a line as a write takes them; write a setting or a session builtin
 /commands    every builtin: word, `arg` if it takes one, `root` or `pane` (the ctl that takes it), a setting's values
 /layout      one line per column, left to right: serial index x width current|notcurrent
-             empty|full pane-serials...; then active <serial> (- when no column has the keyboard)
+             empty|full pane-serials...; then active <serial>: the active column, where
+             pane/new and a look place a pane next (- when there is none)
 /tag         the workspace tag; > replaces it, >> appends, one line
 /col/<n>/tag the tag of the column with serial n, the same way
 /pane/new    open it to make a pane; the read answers that pane's serial. A session holds