no input on channel strip when I try to create multichannel patch

Sorry I'm a newbie so be gentle! Having installed MainStage 3 and the latest drivers for my Roland RD-700nx and following the instructions to set up the midi I find that when I add a channel to a patch there is no input and it doesn't then matter which instruments I select because they can't play. If I just create a new patch from the patch library there is no problems and the channel plays and works as expected. This is what my midi setup looks like

What am I doing wrong?