Scratch that - this still feels really unfinished to use. And with VS Code now having a nice Outline preview, it just makes things worse!

There are a few issues I've opened in VS Code that might make it possible for us to use the built-in Outline view for this:

microsoft/vscode#51332
microsoft/vscode#51334

but why I still can't use this new featuer (Preview: Flutter Outline) in my VS code?

@winsonet can you be more specific - what do you mean you can't use it? Did you enable it in the user settings, and check you have version v3.3 of the Dart and Flutter extensions? See https://dartcode.org/releases/v3-3/#preview-flutter-outline for notes on this.

If you're still having issues, please open an issue with explicit details on what you're seeing and I can take a look.

Yes, I will open an issue for that, thanks!