If I understand correctly, you’re saying clicking on the mixer only gives the “source” section of the full list?
I’ve never really cared, but if I think about it, to me it makes sense to narrow a menu down when clicking on something specific; but perhaps LP has a good suggestion, left clicking on it in the sequencer view would open like in the mixer view, but right click the full. Otherwise, now that I’ve thought about it, that option or I think I’d prefer clicking on it and only getting the source menu. If I wanted properties for everything, I’d click a more general area. I’m pretty sure other programs do that too; focus menus in specific areas but if right clicked in general areas (like on headings and such) give the full menu.
Still, I don’t greatly care either way! Would only be a minor convenience to me.