[Bug] Korean (Hangul) IME input broken in Power Query Editor — characters get overwritten when M Int

[ken]

• [Cross-posting from a previous report on the Issues board: link — posting again under a more visible category since the original has been sitting at "New" status with no triage for over a month. This bug is severely impacting Korean Power BI users.]

== Summary ==

When typing Korean (Hangul) in the Power Query Editor (both the Formula Bar and the Advanced Editor), characters overwrite each other instead of composing normally. The bug only occurs when M Intellisense is ON.

== Reproduction ==

1. Windows 11 with Microsoft Korean IME active
2. Open Power BI Desktop → Power Query Editor
3. Make sure M Intellisense is ON (default)
4. Try typing "고객주소" (Customer Address) in the Formula Bar or Advanced Editor

Expected: 고 → 고객 → 고객주 → 고객주소
Actual: 고 → 객 → 주 → 소 (each new syllable replaces the previous one)

== Root cause (confirmed by toggle test) ==

• M Intellisense ON → bug reproduces 100%
• M Intellisense OFF → typing works correctly

The Intellisense engine is intercepting IME composition events and committing each syllable prematurely, breaking Hangul composition.

== Why this matters ==

• Korean column names, comments, and string literals are extremely common in real-world Korean Power BI projects.
• Only workarounds available: (a) type in Notepad and copy-paste — extremely tedious; (b) press Space+Backspace after every syllable — unusable for long text; (c) disable M Intellisense entirely — losing Intellisense is not acceptable.
• This likely affects all CJK IME users (Chinese, Japanese, Korean), not just Korean.

== Reproduction caveat for triage ==

Simply installing the Korean language pack on Windows is NOT enough. You must actually switch the active input method to Korean IME (Win+Space) and type in Korean. Past reports have likely been dismissed as "Cannot Reproduce" because testers only typed English while having Korean installed.

== Environment ==

• Power BI Desktop: March 2026 (latest as of report date)
• OS: Windows 11
• IME: Microsoft IME (Korean)

== Korean summary (한글 요약) ==

Power Query 편집기(수식 입력줄, 고급 편집기)에서 한글 입력 시, M Intellisense가 켜져 있으면 이전 음절이 다음 음절에 덮어써져서 글자가 정상적으로 조합되지 않습니다. "고객주소"를 입력하면 마지막 글자 "소"만 남습니다. M Intellisense를 끄면 정상 작동하지만, Intellisense 없이 M 코드를 작성하라는 것은 현실적인 해결책이 아닙니다. 한국 Power BI 사용자에게 매우 큰 불편을 주는 이슈이며, 약 한 달 전 Issues 보드에 보고했으나 상태 변경 없이 방치되어 재제출합니다.

Please prioritize. Thank you.