Clicking the “eye button” found at the right of the tool bar of the Edit tool displays a menu.
This menu allows to toggle the visibility of elements belonging to certain categories. Simply uncheck a menu entry to “hide” in the Edit tool all the elements belonging to the corresponding category.
Even when an available element has been made hidden, it's still possible to specify it by typing its name (no auto-completion though) in the text field of the Edit tool.
(Hidden by default unless stated otherwise)
[a] Always visible when ancestor element is
[b] Always visible when ancestor element is