Dead key used as a shortcut or first key of a chord leaves dead-key composition active

Type: Bug

There are existing issues related to dead keys and international keyboard layouts, but I couldn't find one covering dead keys used in a shortcut by itself, or as the first key of a sequential chord. This issue describes that specific case.

**Steps to reproduce**

1. Use the Finnish keyboard layout.
2. Add a keybinding that uses a dead key as a physical-key shortcut or the first part of a chord, for example:

```json
{
"key": "[BracketRight] d",
"command": "workbench.action.showCommands"
}
```

(`BracketRight` is the `¨` dead key on the Finnish layout.)
3. Open a text editor.
4. Press `¨ d`.

**Expected Result**

* The command executes.
* No text is inserted into the field.
* The dead-key composition state is cleared because the key sequence was consumed as a shortcut.

**Actual Result**

* The command executes correctly.
* A literal `d` is also inserted into the text field.

This only happens when the first key is a dead key.

For comparison, using:

```json
{
"key": "[BracketLeft] d",
"command": "workbench.action.showCommands"
}
```

(where `BracketLeft` is `å` on the Finnish layout, not a dead key) executes the command without inserting text.

**Additional Observations**

Using a single-key shortcut bound to the dead key:

```json
{
"key": "[BracketRight]",
"command": "workbench.action.showCommands"
}
```

does not immediately insert any text, but the dead-key composition remains active after the command executes.

The next keypress behaves as if the dead key had been typed normally:

* Pressing `e` produces `ë`.
* Pressing `d` (which does not have a composed form) inserts `¨d`.

This suggests the shortcut consumes the keyboard event but does not clear the pending dead-key composition state.

The same behavior occurs with extensions disabled, so it does not appear to be caused by VSCodeVim or another extension.

**Keyboard Shortcuts Troubleshooting Log**

The troubleshooting log shows that the shortcut is matched and invoked normally, with no additional `keydown` events corresponding to the inserted character. For example:

```
2026-07-16 16:21:27.994 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-07-16 16:21:27.995 [info] [Window] [KeybindingService]: | Resolving ;
2026-07-16 16:21:27.995 [info] [Window] [KeybindingService]: \ From 1 keybinding entries, awaiting 1 more chord(s), when: no when condition, source: user.
2026-07-16 16:21:27.996 [info] [Window] [KeybindingService]: / Received keydown event - modifiers: [], code: BracketRight, keyCode: 186, key: Dead
2026-07-16 16:21:27.996 [info] [Window] [KeybindingService]: | Converted keydown event - modifiers: [], code: BracketRight, keyCode: 85 (';')
2026-07-16 16:21:27.996 [info] [Window] [KeybindingService]: | Resolving ;
2026-07-16 16:21:27.999 [info] [Window] [KeybindingService]: \ From 1 keybinding entries, awaiting 1 more chord(s), when: no when condition, source: user.
2026-07-16 16:21:28.001 [info] [Window] [KeybindingService]: + Entering multi-chord mode...
2026-07-16 16:21:28.253 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-07-16 16:21:28.254 [info] [Window] [KeybindingService]: | Resolving ;,D
2026-07-16 16:21:28.254 [info] [Window] [KeybindingService]: \ From 1 keybinding entries, matched workbench.action.showCommands, when: no when condition, source: user.
2026-07-16 16:21:28.255 [info] [Window] [KeybindingService]: / Received keydown event - modifiers: [], code: KeyD, keyCode: 68, key: d
2026-07-16 16:21:28.255 [info] [Window] [KeybindingService]: | Converted keydown event - modifiers: [], code: KeyD, keyCode: 34 ('D')
2026-07-16 16:21:28.256 [info] [Window] [KeybindingService]: | Resolving ;,D
2026-07-16 16:21:28.256 [info] [Window] [KeybindingService]: \ From 1 keybinding entries, matched workbench.action.showCommands, when: no when condition, source: user.
2026-07-16 16:21:28.270 [info] [Window] [KeybindingService]: + Invoking command workbench.action.showCommands.
```

No additional keyboard events are logged, even though a literal `d` is inserted into the text field afterwards.

This suggests the extra character is coming from the text composition/dead-key input pipeline rather than the keybinding service.

VS Code version: Code 1.129.0 (125df4672b8a6a34975303c6b0baa124e560a4f7, 2026-07-15T00:08:44Z)
OS version: Windows_NT x64 10.0.26200
Modes:

System Info

|Item|Value|
|---|---|
|CPUs|13th Gen Intel(R) Core(TM) i5-1335U (12 x 2496)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x8086, DEVICE=0xa7a1 [Intel(R) Iris(R) Xe Graphics], DRIVER_VENDOR=Intel, DRIVER_VERSION=31.0.101.5382 *ACTIVE*
GPU1: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8521
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)|15.69GB (3.77GB free)|
|Process Argv|--crash-reporter-id 72398e6e-23bc-49ee-aaa8-393e17700b2b|
|Screen Reader|no|
|VM|0%|
Extensions disabled
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