Aren't you lucky that the person who scripted SSS is right here?
Well, the design of SSS is different than other libraries, so we opted not to offer MIDI drag&drop, because editing them would be less than obvious, since nearly every hit is preceeded by a preroll sample of certain duration, and so on - not only would the MIDI itself look weird, but editing it would in a lot of cases mess things up considerably. So, you can only edit patterns via the GUI and play them back via keys. That's all there's to it.