So, I got that keyboard (Model WKB-1500, FFC ID: GM8WKB1500) and I'm having some bugs:

Keyboard must be in Pair mode to connect ALWAYS, because of this, I believe it goes into a disconnect/reconnect loop sometimes (a message saying "BT Keyboard want to reconnect Yes/No" appears but the keyboard never reconnects - and btinput still shows a green dot next to it.) Most other Bluetooth input devices I have ever used (mice, keyboards) seem to do a "quick reconnect" after pairing for the first time.

Also, what keyboard layout are you using? It seems USA. Is there any way you can recognize the layout, or provide a setting for it? Maybe something based on this, defining a keyboard layout for specific Bluetooth ID? This keyboard is UK layout (maybe because I bought it from Amazon UK, now that I think of it...).