No placement leaves a pane shorter than its tag and two rows

Placement could split a pane down to a tag and one row, or give a new one
less. Every placement now checks the pane it made and each pane it shrank
against its tag (wrapped at its width) plus two rows: where they lack the
room, the column's tallest pane is halved instead, and where none can give
it the new pane is refused with "no space for a pane in that column"
(ENOSPC over 9P) and closed at the step's end, once its maker is done with
it. splitBelow and splitParent leave two body rows (a boot layout, split
before any row exists, is as before). Re-recorded by name: lookpanes (panes
one or two rows lower) and splitparent (the 6-row squeeze now refuses);
fs.py closes the scratches and long-named panes it no longer needs, since
its 24-row session filled.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/docs/tags.md b/docs/tags.md
index b8322aa9..5c4492bc 100644
--- a/docs/tags.md
+++ b/docs/tags.md
@@ -234,6 +234,13 @@ Every new pane goes through one placement, chosen by the `Placement` setting:
 it, in an init file, a tag or the root ctl; bare `Placement` flips it; `SPC c
 p` is its leader path, and `Config` reports it.
 
+Under either, no placement leaves a pane, new or split, shorter than its tag
+and two body rows (acme's minht keeps one). Where the place chosen has not
+that room, the column's tallest pane is halved instead; where no pane of the
+column can give it, the new pane is refused and closed, with `no space for a
+pane in that column: each keeps its tag and 2 rows` (a 9P write or open of
+`pane/new` fails with it, ENOSPC). A pane alone in its column always fits.
+
 `Placement acme` is acme's makenewwindow (util.c:449-495). The core keeps
 acme's *active column* (activecol, dat.c:37): the column last typed in
 (acme.c:487), clicked in with the select button (acme.c:659), dropped into by