Successful string setters duplicate the new string before freeing the
old one, rebuild parsed text while set up, and request full redraw. They
do not request parent relayout. Copy failure leaves the old string and
parsed text unchanged, but the original tag still reaches superclass
notification processing. The setter returns the superclass result and
does not report copy failure separately.
Setup returns FALSE on Area failure, otherwise TRUE even if text-engine
allocation fails. Bounds measurement tolerates NULL, but AskMinMax and
Draw dereference the parsed object without checking it. Constructor copy
failure may fall back to an empty string; construction fails only if
either final string remains NULL. Repeated constructor string tags can
leak earlier copies.
Draw calls Area, clips to the content rectangle and centers the parsed
block vertically. Horizontal alignment comes from the text engine. Pure
update requests return zero while the private update field is zero; this
class never sets it to a nonzero value in active code. Normal drawing
returns TRUE and resets that field. Show converts the superclass result
to BOOL; Hide returns it unchanged. Import and Export are local no-ops
returning zero without delegating to Area.