High priority: bare left/right arrow hijacks cursor key for session navigation, discarding in-progress input (data loss)

Summary (high priority — causes data loss)

In the interactive CLI, the bare left/right arrow keys are overloaded for session navigation. Specifically:

• Left arrow opens the Sessions sidebar.
• A second left arrow within ~70–450 ms starts a new session (a double-tap gesture; the timing window is hardcoded).
• Right arrow jumps to the Agents tab.

This overloads the single most fundamental cursor key in any text field, and — most importantly — it silently discards in-progress input (a correction/follow-up I was composing), with no confirmation and no auto-stash.

Core principle: bare arrow keys should not be app keybindings in a CLI

Binding bare (unmodified) arrow keys to application actions is a fundamental anti-pattern for a terminal/CLI program. In a text interface the arrow keys have exactly one universally understood job — move the cursor. Users rely on that contract from every shell, REPL, and terminal editor. Any application-level navigation (sidebars, tabs, session switching, new session) should be bound to a modifier or leader chord (e.g. ctrl+…, or the existing ctrl+x → … pattern), never to a naked arrow key. Overloading bare arrows — especially with a destructive action — guarantees accidental, muscle-memory-driven mistakes.

Why this is high priority

• Data loss: while composing a correction or follow-up (often while the agent is working), reaching for the arrow key out of habit triggers navigation / a new session and destroys the correction I was in the middle of writing. Silent loss of user input to a stray cursor keypress is a serious defect, not a cosmetic one.
• Violates universal expectations: left/right arrows mean "move the cursor" in every shell, editor, and text field. Overloading them — especially with a destructive double-tap gesture — breaks muscle memory everyone has.
• No escape hatch: there is no setting to disable or rebind this in /settings or settings.json, and the binding is not listed in the public keyboard-shortcut help. It's effectively hidden and unavoidable.

Steps to reproduce

1. Start copilot (interactive).
2. Press Left (for example while composing or correcting a prompt, or while the agent is working).
   • The Sessions sidebar opens.
3. Press Left again quickly (within ~70–450 ms).
   • A new session is started and any in-progress prompt/correction is discarded.

Note: the exact conditions under which a bare arrow is captured for navigation vs. cursor movement are not documented; the observed effect is that a correction in progress can be lost.

Expected behavior

• Bare left/right arrows should only move the cursor. They should never trigger navigation or start a new session.
• In-progress input must never be discarded without confirmation or an automatic stash.

Suggested fixes (any one resolves it)

1. Don't bind bare left/right to navigation — require a modifier or leader chord (e.g. ctrl+x → …, consistent with the existing ctrl+x → h to hide the sidebar).
2. Add a setting to disable arrow-key session navigation.
3. Never discard in-progress input without confirmation or auto-stash.
4. At minimum, remove the destructive double-tap-left → new-session binding.

Environment

• Copilot CLI: 1.0.71-3
• OS: Windows

まず、入力を作成している間に、一覧にある左矢印とダブルタップの手順を使い、Windows のインタラクティブ CLI での動作を再現します。/settings と settings.json で参照されているキーボードショートカットと設定領域を確認します。矢印キー単体でカーソルが移動し、ナビゲーション中に入力途中の入力が破棄されなければ完了です。