Anker BT keyboard pairs, but doesn't show up as input device?

I have an Anker BT keyboard AK-A7726111. Works fine on my LG G3. Also worked fine with N7.

On the 8.4/SM320 it pairs fine, but I find no way to use it.. it does not appear as an input device.

What is the secret? (other than root/flash something else)

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