A dialog that draws a route graph (message paths, the trophy case, the packet
viewer) paints braille and node-type marks. On a terminal whose font lacks a
glyph, the double-width fallback shoves that row right and smears a static cell
— a box border — that prompt_toolkit's differential renderer never rewrites (it
only redraws each row up to its new content and only erases a shortened tail),
so the fragment lingers once a scroll slides the offending row away.
The map fixes its own case by scrubbing two right-edge columns after a pan, but
that only works for a full-frame panel whose border sits at the terminal edge;
a route-graph dialog is a centred box (or, on an empty stack, a full-frame base)
whose smear can land anywhere, so edge geometry can't target it reliably.
Instead: a screen opts in with `smears = True`, and on a scroll key the session
reflushes — fills pt's remembered frame with a sentinel so the next diff rewrites
every cell *in place* and erase-to-end-of-lines each tail, scrubbing the leftover
wherever it sits. Because the cached frame is kept (not dropped), pt overwrites
rather than erasing first, so there's no blank-flash flicker. Plain dialogs keep
the efficient differential paint untouched; the map/atlas keep their own edge
scrub. Functionality is unchanged — only the smear is cleaned.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Jean-Pierre MartineauandClaude Opus 4.8
82ed64ffcd