You can open Flutter Inspector by following this steps:

1. You have to run your project first (flutter run -d chrome)
2. press Shift+Ctrl+p to open command pallete.
3. type Flutter:Open DevTools
4. you can choose Flutter:Open DevTools in Web Browser
5. connect to running app : (search the url in your flutter terminal) for example: The Flutter DevTools debugger and profiler on Chrome is available at: http://127.0.0.1:9101?uri=http://127.0.0.1:59007/18gRA86MFGU=
6. enter the url. then the flutter inspector will be shown