Ability to customize Sidebar items

Sidebar looks great, but I’d like to be able to customize what shows up there.

Although having History, Favorites and Sets can be useful, I don’t think it should be imposed.

I want to be able to add (and name) my own sections, and organize items the way I want in there, ideally with option to create folders and subfolders.

Ideally I’d also want the option to disable automatically showing linked objects as children in the sidebar. I’d rather have a simple uncluttered main navigation in the sidebar.