With local echo on, committed text sits in the LocalEchoOverlay and does not
reach the PTY before Enter, so the PTY cursor that places the preview span
stays at the prompt start. The span's z-index 6 only counts inside
.xterm-helpers (its own z-index 5 stacking context), and the overlay is a
z-index 7 layer whose first line is opaque from the prompt column, so every
composition after the first one in a prompt was drawn under the overlay.
- xterm-zerolag-input: add setComposition(text) and a composition getter.
The overlay draws the composition as an underlined, aria-hidden tail after
its pending text, through the same wrapping and grow-upward layout. It is
never part of pendingText, hasPending or anything sent; clear() and
removeChar() drop it, and rerender()/refreshFont() keep it.
- terminal-ui.js: while local echo shows typed text (on, and not handed back
to PTY echo by a nav key), render and clear the preview through
setComposition. The helper span stays for local echo off, and as the
fallback when the overlay cannot place the text (no prompt found).
- Browser test against real xterm 6, the overlay bundled from its source
and styles.css: a second composition after pending text is the topmost
element after that text, and the commit lands in the overlay once. Unit
tests for setComposition in the package and for the routing in the
structure test.
- CLAUDE.md and architecture-invariants: state the preview's effective layer.
Aamer Akhter
ee1a155e2c