A column can be empty, as acme's can; new panes go where acme's makenewwindow puts them

Newcol makes an empty column; closing a column's last pane leaves it empty with
the keyboard on its tag; Delcol and Joincol alone take a column away; the
session's last pane closing quits. The +New stand-in and replaceStillborn /
stillborn_joiner are gone. Every new pane goes through exec.placeNew, which
follows acme's makenewwindow (active column, empty column whole, blank space,
halving the biggest) or, with Placement pardes, the old rules. ColumnTags is
gone: column tags are always shown. A grip drag shows acme's box cursor.

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

1 files changed, 4 insertions, 4 deletions

diff --git a/src/fs-help.txt b/src/fs-help.txt
index 2b42be1f..0121a831 100644
--- a/src/fs-help.txt
+++ b/src/fs-help.txt
@@ -8,10 +8,10 @@ exec        write a line: a middle click, an editor command word or a shell line
 log         events: new/del/rename/save <serial> <name>, run/exit/send <serial> ..., dump/restore <path>, msg, err
 screen      rendered screen as JSON, frozen from open to close
 listeners   the session's dial addresses
-focus       the serial of the pane with the keyboard; write a serial to give it the keyboard
-ctl         settings, one a line; or Newcol, Dump, Exit (quits, asks once), Kill [w] (stops what pardes ran, w: by first word)
+focus       the serial of the pane with the keyboard (empty on a column tag); write a serial to give it the keyboard
+ctl         settings, one a line; or Newcol (an empty column), Dump, Exit (quits, asks once), Kill [w] (stops what pardes ran, w: by first word)
 commands    every builtin: its word, arg if it takes one, and root or pane: which ctl takes it
-pane/new    open it to make a pane (named +New); the read answers that pane's serial
+pane/new    open it to make a pane (named +New) in the active column, filling it if empty; the read answers its serial
 pane/<n>/   name body tag ctl addr dot limit data xdata sel dirty mark scroll errors (write-only:
             appended to its directory's +Errors pane) event look exec, pty/ on terminals; rmdir closes
 os/, src/   the host filesystem; the editor's own sources (-Dembed-sources=true builds only)
@@ -41,5 +41,5 @@ Pitfalls, one each:
   A terminal's body is a history snapshot frozen per open; pty/data is the live stream.
   exec: a non-builtin line runs as a command pane (ctl's Shell -c; exit N shown, logged), a shell's typed in.
   Through a mount a malformed write is EINVAL, a well-formed one that fails EIO: log's err says why.
-  lock/unlock need a held ctl fd (exec 3>ctl), a held lock fails: retry. A column's last pane -> +New.
+  lock/unlock need a held ctl fd (exec 3>ctl), a held lock fails: retry. A column's last pane leaves it empty; the last pane of all quits.
   Repl python on a terminal's ctl: a .py body's clicks go to it (Repl - unbinds, Repl says it); tags stay commands.