dev tools inspector will non longer open in vscode.

[bsutton]

Just recently the flutter inspector window will no longer load in vscode.

I can open the inspector in the browser (via 'dart devtools') and connect to a debug session and the inspector works fine from the browser.

I've tried enabling vscode logging but the logs show nothing that looks useful .

!! ⚠️ PLEASE REVIEW THIS LOG FOR SENSITIVE INFORMATION BEFORE SHARING ⚠️ !!
Dart Code extension: 3.116.0
Flutter extension: 3.116.0 (activated)

App: Visual Studio Code
App Host: desktop
Version: linux 1.103.0

Workspace type: Flutter (LSP)
Workspace name: hmb

Dart (3.8.1): /home/bsutton/apps/flutter/bin/cache/dart-sdk
Flutter (3.32.8): /home/bsutton/apps/flutter (No device)


Logging Categories:
    General, AnalyzerTiming, CommandProcesses, DartTest, DartToolingDaemon, DAP, VmService, DevTools, FlutterDaemon, FlutterRun, FlutterTest, WebDaemon

Thu Aug 14 2025 [21:21:01 GMT+1000 (Australian Eastern Standard Time)] Log file started
[21:21:01] [DAP] [Info] ==> {"command":"updateSendLogsToClient","arguments":{"enabled":true},"type":"request","seq":16}
[21:21:01] [DAP] [Info] <== {"seq":215,"type":"response","command":"updateSendLogsToClient","request_seq":16,"success":true}
[21:21:03] [General] [Info] Using only available debug session
[21:21:03] [General] [Info] Exposing URL: ws://127.0.0.1:42011/Pdv4EweynDY%3D/ws
[21:21:03] [General] [Info] Mapping URI: http://127.0.0.1:42011/Pdv4EweynDY%3D/ws
[21:21:03] [General] [Info] Mapped URI: http://127.0.0.1:42011/Pdv4EweynDY%3D/ws
[21:21:03] [General] [Info] Mapped URL: http://127.0.0.1:42011/Pdv4EweynDY%3D/ws
[21:21:03] [General] [Info] Final URL: ws://127.0.0.1:42011/Pdv4EweynDY=/ws
Thu Aug 14 2025 [21:21:06 GMT+1000 (Australian Eastern Standard Time)] Log file ended

flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.32.8, on Ubuntu 25.04 6.11.0-26-generic, locale en_AU.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.1)
[✓] Chrome - develop for the web
[✓] Linux toolchain - develop for Linux desktop
[✓] Android Studio (version 2024.3.2)
[✓] VS Code (version unknown)
    ✗ Unable to determine VS Code version.
[✓] Connected device (2 available)
[✓] Network resources

• No issues found!

[bsutton]

I've just tried disabling all vscode extensions except for flutter and dart and the inspect is still broken.

Here is a video showing what occurs when I click the inspector icon in the debug toolbar.

Screencast.From.2025-08-14.21-31-25.mp4

[elliette]

Hi @bsutton - this issue looks like it occurred on an older version of DevTools. Are you able to upgrade to the latest Flutter stable (3.35, DevTools 2.48.0) and see if this still occurs?

[bsutton]

I've upgraded and the symptoms are identical.

flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.35.1, on Ubuntu 25.04 6.11.0-26-generic, locale en_AU.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.1)
[✓] Chrome - develop for the web
[✓] Linux toolchain - develop for Linux desktop
[✓] Android Studio (version 2024.3.2)
[✓] VS Code (version 1.103.0)
[✓] Connected device (2 available)
[✓] Network resources

• No issues found!

in case it wasn't clear I'm building/debugging to linux desktop (I've been doing this for some 18 months with no issues for quite some time).

[elliette]

Thanks for confirming! To help us narrow down the cause, could you check a few things:

1. Whether the inspector loads when you run "Flutter: Open DevTools" from the VS Code command palette.
2. Whether you can load the other side panels that are served by Flutter DevTools? In your screenshot, those are the Property Editor panel and the Flutter panel, below the Inspector panel. (see screenshot below)
3. Whether you can load the Inspector in "beside" mode instead of "sidebar" mode (see https://dartcode.org/releases/v3-108/#experimental-devtools-embedded-in-sidebar) In your VS Code settings.json, add

"dart.devToolsLocation": {
	"inspector": "beside",
}

[bsutton]

1). Whether the inspector loads when you run "Flutter: Open DevTools" from the VS Code command palette.

A new window opens but its empty:

2). open other side panels.
neither of the icons (property editor or flutter side bar) open - the focus changes to the side bar but no content is displayed.

3): Whether you can load the Inspector in "beside" mode instead of "sidebar" mode (see https://dartcode.org/releases/v3-108/#experimental-devtools-embedded-in-sidebar) In your VS Code settings.json, add

I updated my settings to:

    // Enable the experiment
    "dart.experimentalSidebarDevTools": true,
    // Customise which sections are shown in the sidebar, in an editor tab, or external browser.
    "dart.devToolsLocation": {
        "inspector": "beside",     // Embed the inspector in sidebar
        "cpu-profiler": "external", // Open the CPU profiler in external browser
        "default": "beside",        // Default other tabs to an editor tab beside the current code editor
    },
}

The widget inspector window opens but no content is displayed.

Screencast.From.2025-08-16.09-37-10.mp4

If I set the 'inspector' to 'external' it opens in a browser and shows the widget tree correctly.
I also tried setting it explicitly to 'sidebar' and it again did not work.