The problem is MIDI learn for controllers in Studio One is limited. I have one with knobs and buttons, and if knobs settings up nice and easy, the buttons are not, because they send MIDI Note instead of CC.
I figured out how to pass it through low level XML file editing after which buttons appears in External Device view, but it would be great to have advanced MIDI Learn mode, where S1 itself can easily receive ALL the (unusual) buttons, knobs, triggers etc.
Same issue with Assign Commands — they don't have commands for global and advanced functions, for example: Selected Plugin Deactivate or Bypass, Deactivate All Plugin Column on Track, Adding preselected Plugin and other similar. Some of this works some how if choose Mackie Control instead, but in this way the commands are pre linked on random buttons and not customizable.
Having more global and advanced Assign Commands will let to create fantastic integration and will significantly improve the workflow with external controllers.