I have the wireless Blademaster Pro mechanical keyboard, currently I have it connected via USB.
Ctrl and Alt keys are working fine but the Super key (labeled WIN and Option) does nothing when pressed. It should make all windows viable and allow tabbing between them. I can confirm this using another keyboard.
xev pressing Super on my old keyboard I see:
PropertyNotify event, serial 37, synthetic NO, window 0x3c00001, atom 0x18b (_GTK_EDGE_CONSTRAINTS), time 22310600, state PropertyNewValue
But on my new keyboard, nothing is output. Also while all other keys are backlit with red, the WIN key is backlit blue...