I have been comparing thunar and nautilus to decide if I wanted to switch file manager. Both have a sidebar on the left with shortcuts to various folders (home, documents, downloads...), to which you can add your own folders. I have noticed that when I add a folder to the sidebar of one of the two, it also appears in the sidebar of the other.
Is this specific to those two programs, each knowing how to synchronize to the other ? Or is it something more general, and if so at what level is it defined ? Gnome, Ubuntu, X11 ..?