You make a good point. I'll fix this ASAP. I was also under the impression that the meta key mapped to the Windows key, but perhaps I'm wrong.

Edit: Just updated the shortcut to control + m. Let me know if you continue to experience troubles.

Yes, event.altKey would seem a better choice as it maps to Alt on Windows and Option on the Mac. Not sure about Chromebooks (which don't even have any modifier keys other than Shift) or Linux though. Or mobile browsers.

I always thought that the key with the Windows logo was the meta key. Does it map out to something different?