v2.100.5 and v2.110.4 formatter ignores .editorconfig

Type: Bug

Issue Description

v2.100.5 and v2.110.4 formatter ignores .editorconfig
I have downgraded to v2.97.38
For v2.97.38, I recommend adding the following settings to settings.json
Detail: #8709

{
  "[csharp]": {
    "editor.formatOnType": false
  }
}

• How to downgrade

1. Open the extension
2. Click the V (dropdown?) to the right of the Uninstall button
3. Click "Install Specific Version..."

4. Click "2.97.38"
5. Click "X" button and restart VSCode
   Note: "Restart Extension" button does not work

Explanation in Japanese
https://zenn.dev/umitempa/articles/99e0080f767000

Steps to Reproduce

1. Downgrade to v2.97.38
2. Click "X" button and restart VSCode
   Note: "Restart Extension" button does not work
3. Create the following files in the same directory

.vscode\settings.json

{
  "editor.formatOnSave": true,
  "[csharp]": {
    "editor.defaultFormatter": "ms-dotnettools.csharp",
    "editor.formatOnType": false
  }
}

.editorconfig

root = true

[*.cs]
indent_size = 2
indent_style = space
csharp_new_line_before_open_brace = none

Program.cs

using System;

class Program
{
  static void Main()
  {
    Console.WriteLine("Hello, World!");
  }
}

4. Format Program.cs
   The code should look like this after formatting

using System;

class Program {
  static void Main() {
    Console.WriteLine("Hello, World!");
  }
}

5. Update to v2.110.4
6. Click "X" button and restart VSCode
   Note: "Restart Extension" button doesn't work
7. Format Program.cs

Expected Behavior

It should be the same as step 4

Actual Behavior

Formatter ignores .editorconfig

using System;

class Program
{
  static void Main()
  {
    Console.WriteLine("Hello, World!");
  }
}

Extension version: 2.100.5
VS Code version: Code 1.107.1 (994fd12f8d3a5aa16f17d42c041e5809167e845a, 2025-12-17T14:15:14.850Z)
OS version: Windows_NT x64 10.0.26100
Modes:

Logs

C# log

Details

2026-01-08 19:28:02.691 [info] Locating .NET runtime version 9.0.1
2026-01-08 19:28:02.726 [info] Dotnet path: C:\Program Files\dotnet\dotnet.exe
2026-01-08 19:28:02.726 [info] Activating C# standalone...
2026-01-08 19:28:02.990 [info] [stdout] info: Program[0]
      Server started with process ID 17200

2026-01-08 19:28:03.449 [info] [stdout] {"pipeName":"\\\\.\\pipe\\3039adca"}

2026-01-08 19:28:03.449 [info] received named pipe information from server
2026-01-08 19:28:03.449 [info] client has connected to server
2026-01-08 19:28:03.544 [info] [Program] Language server initialized

C# LSP トレース ログ log

Details

Environment Information

VSCode version: 1.107.1
C# Extension: 2.100.5
Using OmniSharp: false

Dotnet Information

.NET SDK: Version: 10.0.101 Commit: fad253f51b Workload version: 10.0.100-manifests.9f71effe MSBuild version: 18.0.6+fad253f51

Runtime Environment:
OS Name: Windows
OS Version: 10.0.26100
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\10.0.101\

.NET workloads installed:
There are no installed workloads to display.
Configured to use workload sets when installing new manifests.
No workload sets are installed. Run "dotnet workload restore" to install a workload set.

Host:
Version: 10.0.1
Architecture: x64
Commit: fad253f51b

.NET SDKs installed:
10.0.101 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 10.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 10.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.22 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 10.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
DOTNET_CLI_TELEMETRY_OPTOUT [true]
DOTNET_CLI_UI_LANGUAGE [en-US]

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Visual Studio Code Extensions

Extension	Author	Version	Folder Name
csharp	ms-dotnettools	2.100.5	ms-dotnettools.csharp-2.100.5-win32-x64
hexeditor	ms-vscode	1.11.1	ms-vscode.hexeditor-1.11.1
prettier-vscode	esbenp	11.0.2	esbenp.prettier-vscode-11.0.2
vscode-dotnet-runtime	ms-dotnettools	3.0.0	ms-dotnettools.vscode-dotnet-runtime-3.0.0
vscode-eslint	dbaeumer	3.0.20	dbaeumer.vscode-eslint-3.0.20
vscode-language-pack-ja	MS-CEINTL	1.107.2025121009	ms-ceintl.vscode-language-pack-ja-1.107.2025121009

C# Settings

Setting	Value
preferCSharpExtension	false
compilerDiagnosticScope	openFiles
analyzerDiagnosticScope	openFiles
enableXamlTools	true
useServerGC	true

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-14400F (16 x 2496)
GPU Status	2d_canvas: enabled 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 webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	31.84GB (22.73GB free)
Process Argv
Screen Reader	no
VM	0%