I have a Drevo Calibur 71 USB/Bluetooth keyboard that was working fine until recently.
The problem I am having is that the Super key is not functioning as it should. Actually it does nothing. It works fine on the laptop's keyboard.
I checked a couple of similar questions that involved either a keyboard key that disables the Super key (I don't think this keyboard has one) or using the Tweak Tool. None worked so far.
What might be the problem especially that this thing is recently. They key used to work just fine a few months ago.
PS: I am on Ubuntu Gnome 16.04.5
It turns out the keyboard's different modes and can disable or switch keys. At the time I asked the question I didn't have access to the only reference card that came with the keyboard however I have shared it below for reference.
PS: I was also having issues with the Left Ctrl key toggling the CapsLock. Now I understand why and I was able to disable it.