I have recently acquired a mechanical keyboard Corsair K70 (non RGB model) and have successfully used it with macOS Sierra (10.12.6). Everything works as expected with the exception of certain keyboard shortcuts within Xcode. One of which is Cmd + Left Click on a function name, which brings up an action popup menu as shown in the image below:
The same goes for the function documentation Option + Left Click:
The shortcuts work as expected when using the built in keyboard on the MacBook Pro (15-inch, 2017), but they do not work when using the externally connected (usb) keyboard. The layout is English ISO/European as shown in the image below:
When trying the shortcuts on the mechanical keyboard, it feels as if the UI is glitchy and not fully processing the shortcut.