Midi remote control not working in Linux

I am using Musescore 3.0.5 with Linux Mint 18.3 Cinnamon 64-bit.
I cannot get Midi remote control to work - it is grayed out in note input under preferences.
The tick box will not accept a tick. All the other note input functions of Musescore seem to work.
It works fine under Windows 10 - same computer.
I would be grateful for any help.