microsoft/Terminal

Korean IME: composing character still moves to wrong position on arrow key press (v1.24.11321.0)

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#20244 opened on May 19, 2026

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Area-RenderingHelp WantedIssue-BugPriority-3Product-Terminal

Description

Description

When composing a Korean (Hangul) character and pressing an arrow key before the composition is finalized, the composing character is inserted at the new cursor position instead of staying at the original position.

This was reportedly fixed in #20039 and #20041, but the issue still reproduces on v1.24.11321.0 (stable).

Steps to reproduce

  1. Open Windows Terminal (any shell: cmd, PowerShell, or WSL bash)
  2. Type Korean text, e.g. 가나 and begin composing the next character (e.g. ㄷ)
  3. Before finalizing the composition (without pressing Space/Enter), press an arrow key (← or →)
  4. The composing character (ㄷ) moves to the cursor's new position

Expected behavior

The composing character should be finalized at its original position before the cursor moves.

Actual behavior

The composing character follows the cursor and is inserted at the wrong position.

Environment

  • Windows Terminal: v1.24.11321.0 (stable)
  • Windows: 23H2
  • Shells tested: cmd, PowerShell 5.1, WSL2 bash
  • Microsoft IME (legacy mode)
  • conhost.exe does NOT have this issue — only Windows Terminal

Contributor guide

Tech stack
cpp
Domain
desktop
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++Windows Terminal architectureIME handling
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Start by reviewing the previous fixes in #20039 and #20041 to understand what was changed and why the issue persists. Then, examine the input handling code in the Terminal codebase, likely in the `src/terminal/input/` directory, focusing on how IME composition events and keyboard input are processed. Look for where the composing character position is updated and why arrow keys trigger a move before finalization.