+Errors with no room anywhere logs its text rather than fail the Edit

Edit's p and = put their output in +Errors, and when its column had no
room the placement refusal failed the whole Edit. +Errors now tries every
column with room, the last first, and with none its text is logged as msg
records, a line each; the Edit succeeds.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/docs/tags.md b/docs/tags.md
index 5c4492bc..cee8e335 100644
--- a/docs/tags.md
+++ b/docs/tags.md
@@ -240,6 +240,9 @@ 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.
+A `+Errors` pane goes to any column with room, the last first; with none,
+what it would have shown (an Edit's `p` or `=`, a write to `errors`) is
+logged as `msg` records, a line each, and the Edit still succeeds.
 
 `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