The components attribute pop-up is something I use a lot. It would be handy and out of the way if it could be one of the sections of the tray, since the tray is always out there anyway.
The reason for this is probably that the Dynamic components function is a plugin created by the SU team and shipping and installing together with it. The Sandbox tools are similar. Perhaps it would be time to integrate them into the core, with some fixes and enhancements.