A word at /tagexec or a column's exec that makes, acts on and focuses no pane reads back nothing

Newcol written to /tagexec read back `1`, the pane with the keyboard, which
the word never touched. That was a pane word's fallback (a pane's exec
answers the pane it ran at) applied to a tag no pane owns. A word in a
column's or the workspace's tag now answers the pane it made, refilled, went
to or focused, and otherwise nothing.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/docs/fs.md b/docs/fs.md
index b30ae3ef..75f9fd14 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -156,7 +156,8 @@ fails at the close if it never ends (``unmatched `{'``). A line held past
 1 MiB is refused.
 
 **Answers.** Reading `look`, `exec` or `tagexec` answers the serials the
-last command made, or else the pane it acted on or focused, one a line. An
+last command made, or else the pane it acted on or focused, one a line;
+nothing when it did none of these (`Newcol` at `/tagexec`). An
 open that wrote reads its own last answer; an open that never wrote reads
 the session's last. A read is a stream: once read, the next read on that
 fid is EOF until the next write (or seek to 0). With other clients about,