Editor view unexpectedly scrolls when typing, pressing space/enter, or saving in C# files

[sunrise-oneday]

Describe the Issue

The editor viewport unexpectedly scrolls/jumps upward or downward when typing, triggering IntelliSense, pressing Space, Enter, or saving (Ctrl+S). This happens even when there is plenty of unused space below the editing area, and it shifts the target code away from center, making it impossible to stay focused on the current line.

Steps To Reproduce

1. Open any relatively long C# script in a Unity project.
2. Ensure there is enough empty space below the current editing area.
3. Start typing a variable and trigger IntelliSense suggestions (e.g., type atkEffect.).
4. Press Space, Enter, or Ctrl+S to save.
5. Observe the editor viewport.

Expected Behavior

The editor viewport should remain stable when typing, using IntelliSense, pressing Enter/Space, or saving. No automatic scrolling should occur if there is still visible space for the cursor.

Environment Information

• OS: Windows 11 23H2 (Windows_NT x64 10.0.22631)
• VS Code Version: 1.114.0 (system setup)
• Electron: 39.8.3
• Chromium: 142.0.7444.265
• Node.js: 22.22.1
• V8: 14.2.231.22-electron.0
• Extensions: Visual Studio Tools for Unity (vstuc)
• Unity Version: 2022.3.62f3c1
• VS Code A/B Experiments: None found in About dialog (version 1.114.0)

[jbevain]

Hi @sunrise-oneday, thanks for reaching out. It sounds like a duplicate of #2623 which we've never been able to reproduce.

Does it stop if you disable the setting "Unity Code Model"?

What's your current locale and text input setting? Thanks!

[sunrise-oneday]

@jbevain Thanks for the reply!

I can confirm that after disabling the "Unity > Code Model" setting, the unwanted scrolling completely stopped. So it is definitely related to that feature.

Here are the details you requested:

• VS Code Display Language: zh-cn
• OS Language: Chinese (Simplified, China)
• Input Method: Sogou Pinyin, in English input mode (issue occurred even in English mode

[sunrise-oneday]

@jbevain Quick update with a very important finding:

After I re-enabled the “Unity > Code Model” setting, the unwanted scrolling issue has completely disappeared on my machine. I cannot reproduce it anymore.

The key change on my end is that I recently upgraded Windows 11 from version 23H2 (build 22621.1) to version 25H2(latest). Since the issue was 100% reproducible before the OS upgrade and now it’s completely gone (even with the extension enabled), this strongly suggests the root cause might be tied to a specific Windows text-input framework (TSF) bug that has been fixed in 25H2.

[jbevain]

Wow that's good insight. Thanks for sharing the details. I'm going to close this, feel free to re-open if the issue comes back. I'll ask in the other issue if they can upgrade to 25H2. Thanks again!

[sunrise-oneday]

Hi @jbevain ,

I'm sorry to bother you again, but the issue (editor viewport scrolling randomly when typing, especially with vstuc.enableCodeModel enabled) has returned, and I've now recorded a clear screen capture that demonstrates the problem.

Video of the bug
I've attached/linked a screen recording that shows exactly what happens.

What I've already tried (diagnostics)

1. Extension logs: I checked %APPDATA%\Code\logs\...\exthost\visualstudiotoolsforunity.vstuc\Unity.log — it's only 82 bytes and contains just the dotnet path. No editor interaction, no scroll events.
2. Renderer log No scroll-related keywords.
3. C# LSP trace: I enabled "dotnet.server.trace": "Trace" and examined the C# LSP output, but couldn't see any obvious textDocument/publishDiagnostics or other notifications that correlate with the scrolling.

Because none of the logs seem to capture what the Code Model is doing to the editor, I wasn't able to find a root cause myself.

Additional reproduction detail
I've found that the bug only occurs when the C# file has a large number of lines. In small files it rarely happens, but as soon as I open a file with several hundred lines (like the one I've attached), the random scrolling becomes very easy to reproduce.

I've attached the exact file that I used in the video to trigger the bug.
PlayerAttackerController.cs.txt

Because none of the logs seem to capture what the Code Model is doing to the editor, I wasn't able to find a root cause myself.

I really want to help fix this, so I'm happy to run any additional debugging steps you suggest.

Thank you again for your time!

[jbevain]

@sunrise-oneday no problem. Happy to work with you on finding the root cause. Let us take a deeper look at how we could diagnose this effectively. In the meantime, could you reach out by email? My github alias at microsoft.com. This way we could maybe share custom builds to help figure this out. Thanks!