[Bug] Chinese IME composition text overflows terminal horizontally; candidate window jumps to far right (upstream xterm.js 6.0.0)

[hupeak]

Environment

• Wave Terminal: v0.14.5 (w2), Windows
• Bundled dependency: @xterm/xterm ^6.0.0 (confirmed in package.json)
• IME: Microsoft Pinyin / Sogou (reproducible with any caret-following Chinese IME)

Steps to reproduce

1. Open a terminal block in Wave.
2. Move the cursor toward the right side of the terminal (or just start typing near the end of a line).
3. Type Chinese with an IME so a composition (preedit) string appears.

Actual behavior

• The terminal view expands horizontally / shows horizontal overflow while composing.
• The IME candidate window is anchored to the far right of the terminal, far away from the cursor.

Expected behavior

• The composition (preedit) text is clipped at the terminal's right edge and never widens the layout.
• The IME candidate window stays near the cursor.

Root cause (upstream xterm.js, already confirmed & fixed but unreleased)

xterm.js renders IME composition text in an overlay .composition-view that is position:absolute; white-space:nowrap with no max-width / overflow limit. When the cursor is near the right edge, the composition text extends rightward past the terminal boundary and stretches the container. The hidden helper textarea's width is synced to the composition view's width, so the caret — and therefore the IME candidate window — is pushed to the far right.

This is exactly the upstream bug:

• Chinese IME shows input far from cursor when using AI CLIs xtermjs/xterm.js#5454 — Chinese IME shows input far from cursor (closed as "fixed by #5759 and #5747")
• Fix IME composition text overflowing terminal xtermjs/xterm.js#5747 — "Fix IME composition text overflowing terminal" (merged 2026-03-10, milestone 7.0.0, not yet on npm; latest stable is still 6.0.0)
• Terminal input with IME overflows to outside of the terminal microsoft/vscode#300251 — same symptom in VS Code terminal, resolved by upgrading xterm.js (VS Code 1.112)

Note

Wave's AI chat block is NOT affected — it uses a native DOM input, not the xterm.js composition layer, which confirms the bug lives in the xterm.js terminal component.

Suggested fix

• Bump @xterm/xterm to a release containing #5747 (7.0.0 or a backport), or
• Backport the composition-view clipping (max-width + overflow: hidden, matching ghostty behavior) into Wave's bundled xterm.css.

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