My arduino uno connects perfectly, when I switched to an adafruit metro which is identified specifically in the Windows IDE, it connects when I go to select Arduino Uno/Gen. from the drop down but doesn't auto identify like my Uno. It still works fine even though its not on the supported devices list.
This is a very minor comment, it does work fine once I do those choices from the menu. I am loving this new app!
Please consider adding the adafruit circuit playground as a supported board.