• VSCode Version: Code - Insiders 1.17.0-insider (f7962f0, 2017-09-20T05:10:59.524Z)
• OS Version: Darwin x64 17.0.0
• Extensions: (unimportant, see below)

Steps to Reproduce:

1. Try to use "window.nativeTabs": true option, notice the squiggles and message says Unknown configuration setting
2. If you remove the setting, opening a new window does create a new window
3. If you put the setting back, it is respected, but creating a new window creates (visually) empty native tab bar (previously it showed two tabs, as expected); clicking on the tab creates a new window, as if the whole tab bar is in fact the newly added (looking at 1.17 release notes) "+" button to add a new window/tab
4. Switching windows works, my custom shortcuts are respected etc. all is well, except tabs display

One more thing 😉 bizarrely my insider hasn't been updates since 20th of September (never seen insider go for 10 days without update). Downloading insider from Code's site also yields 20th of Sep version.

Reproduces without extensions: YES (as expected)