Terminal: IME composition text is rendered a few pixels below the cursor line (Korean IME, Windows 11)

https://github.com/user-attachments/assets/97efe406-25a2-42ee-976b-2aaad142f4a1

https://github.com/user-attachments/assets/b191cadb-ea62-4f13-938c-1cc5b3105d42

Type: Bug

Type: Bug

## Description

In the VS Code integrated terminal, text that is still being composed by the
Korean IME (the pre-edit / composition string, before it is committed) is
rendered a few pixels lower than the terminal's text baseline. It appears
slightly below and offset from the cursor position instead of sitting exactly
on the cursor line.

Once the character is committed (space / enter / candidate selection), it is
placed correctly on the line. The problem is purely visual and only affects the
composition overlay, but it is distracting during continuous Korean input.

## Steps to Reproduce

1. On Windows 11, switch the input method to Korean (Microsoft IME).
2. Open the VS Code integrated terminal.
3. Start typing Hangul at the shell prompt, e.g. `ㅎ` -> `한` -> `한ㄱ` -> `한글`.
4. While the syllable is still being composed, observe the vertical position of
the composition text relative to the surrounding terminal text and the cursor.

Expected: the composition text is aligned with the terminal text baseline, on
the same line as the cursor.

Actual: the composition text is drawn a few pixels below the baseline, visibly
offset from the cursor line.

## Scope

- Reproduces in every integrated terminal in VS Code, regardless of shell.
- Does NOT reproduce in the VS Code editor pane — Korean IME composition is
positioned correctly there.
- Does NOT reproduce in any application outside VS Code (Windows Terminal,
browsers, native text fields all behave correctly).

This suggests the problem is specific to the terminal's composition overlay
rather than to the OS IME or to display scaling.

## Things I already tried (none of them changed the behaviour)

- `"terminal.integrated.gpuAcceleration": "off"` (with terminals recreated
afterwards, and with a full restart of VS Code)
- `"terminal.integrated.lineHeight": 1` (default value confirmed)
- Changing `terminal.integrated.fontFamily` to D2Coding, a monospace font that
contains Hangul glyphs, so that no font fallback occurs for Korean characters
- Full restart of VS Code after each change

## Environment

- OS: Windows 11
- VS Code version: About>
- Shell:
- IME: Microsoft Korean IME (default, "use previous version of Microsoft IME"
is OFF)
- Display scaling:
- `window.zoomLevel`: 0
- Does this issue occur when all extensions are disabled?:

## Additional context

A screen recording of the composition offset is attached.

VS Code version: Code 1.135.0 (08d4889f9ec4a1685d257b9b95de036c8e1ce1e5, 2026-08-25T14:26:52Z)
OS version: Windows_NT x64 10.0.26200
Modes:

System Info

|Item|Value|
|---|---|
|CPUs|Intel(R) Core(TM) Ultra 5 225H (14 x 3686)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x8086, DEVICE=0x7d51 [Intel(R) Arc(TM) 130T GPU (15GB)], DRIVER_VENDOR=Intel, DRIVER_VERSION=32.0.101.8826 *ACTIVE*
GPU1: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8972
Machine model name:
Machine model version:
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: disabled_off
trees_in_viz: disabled_off
video_decode: enabled
video_encode: enabled
webgl: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|undefined|
|Memory (System)|30.92GB (17.65GB free)|
|Process Argv|-n --crash-reporter-id d8ecb5de-18f8-44d8-812a-6c66200eb2aa|
|Screen Reader|no|
|VM|0%|
Extensions (14)

Name|Identifier|Author|Version
---|---|---|---
Container Tools|ms-azuretools.vscode-containers|ms-azuretools|2.5.0
Docker|ms-azuretools.vscode-docker|ms-azuretools|2.0.0
Python Debugger|ms-python.debugpy|ms-python|2026.6.0
Python|ms-python.python|ms-python|2026.4.0
Pylance|ms-python.vscode-pylance|ms-python|2026.3.1
Python Environments|ms-python.vscode-python-envs|ms-python|1.36.0
Dev Containers|ms-vscode-remote.remote-containers|ms-vscode-remote|0.466.0
Remote - SSH|ms-vscode-remote.remote-ssh|ms-vscode-remote|0.126.0
Remote - SSH: Editing Configuration Files|ms-vscode-remote.remote-ssh-edit|ms-vscode-remote|0.87.0
WSL|ms-vscode-remote.remote-wsl|ms-vscode-remote|0.104.3
Remote Development|ms-vscode-remote.vscode-remote-extensionpack|ms-vscode-remote|0.26.0
Remote Explorer|ms-vscode.remote-explorer|ms-vscode|0.5.0
Remote - Tunnels|ms-vscode.remote-server|ms-vscode|1.5.3
vscode-pdf|tomoki1207.pdf|tomoki1207|1.2.2

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