Individual items are hierarchically sorted in a tree, divided into groups. Each group appears as another popup menu, items in the base [ROOT] group show up in the context menu itself.
Items which are checked (marked with an [x] sign next to them) will be available by default. The rest will be shown only when you hold the Shift key while opening the context menu (clicking with the right mouse button on a list of tracks, for example).
This configuration does not affect other usage of context menu commands (keyboard shorcuts, custom user interface buttons, etc.).