Allow for sub-systems to aid in quoting and grouping. IE: "Audio - Speakers" or "Audio - Amplifiers" both under "Audio"
I agree, nowadays more AV integrators are also doing more IT systems as well. As an integrator we do AV, IT and Security systems. It would be nice if we can organize order Dtools projects a bit better by having sub-systems. For me is it more and less a no brainer