Japanese IME: Undetermine strings overflows the input box of Copilot chat, it will not be displayed correctly.

[kaorun-cybozu]

Type: Bug

When entering text using the Japanese IME in the Copilot Chat input box, if the undetermine string exceeds the right edge of the window, the text does not wrap properly and scrolls like a marqee tag in the undetermine string.

The True Inline implementation of IME in the Copilot input box is incomplete. Please contact the IME/NLS implementation team.

Steps to reproduce

1. Alt+Ctrl+I ([View]/[Chat]) Show Copilot Chat pane
2. IME on (Alt+~ if you have a US keyboard)
3. Enter some long text with IME
   ex.: 123123123...

Actual behavior

When the undetermine string reaches the right edge of the control, the undetermine string in the line and the duplicated undetermine string wrapped to the next line are separated, and the undetermine string scrolls horizontally like a marqee tag.
This causes the undetermine string to scroll out from the left edge and become invisible, and the conversion of the undetermine string cannot be performed correctly.

Expected behavior

(in Microsoft Teams)

Even if the undetermine string exceeds the right edge of the control, it is text wrapped as an undetermine string and drawn on the next line.

Environment

Version: 1.100.3 (user setup)
Commit: 258e40f
Date: 2025-06-02T13:30:54.273Z
Electron: 34.5.1
ElectronBuildId: 11369351
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Windows_NT arm64 10.0.26200

[tamuratak]

Toggling the editor.experimentalEditContextEnabled setting might fix the issue. See https://code.visualstudio.com/updates/v1_101#_edit-context

[kaorun-cybozu]

Yes! When I set editor.experimentalEditContextEnabled to On, the problem disappeared, the undetermine string was displayed normally, and I was able to input Japanese without any problems. We expect the option to be On by default. Thank you!

[aiday-mar]

Reopening this issue so I can investigate it more later