[BUG] Typing over a selection in the prompt input inserts instead of replacing; Backspace does delete the selection

Environment

• Claude Code 2.1.296
• macOS (Darwin 25.6.0)
• Terminal: iTerm2

Steps

1. Type some text in the prompt input.
2. Select part of it with the mouse.
3. Type a character.

Expected: the typed character replaces the selection, as in any standard text field.

Actual: the character is inserted at the cursor and the selected text stays. Pressing Backspace with the same selection does delete it, so the input knows about the selection; only typed input ignores it.

Workaround: press Backspace first, then type.

Previously reported as #83884 (2.1.221, double-click selection), which was auto-closed as stale on 2026-10-06 without a fix; the bot asked for a new issue if still relevant. Still reproduces on 2.1.296