The history list of a tool stores the most recent events which have been carried out in that tool, or the most recent objects which have been browsed in it.
The History > Items submenu provides a list of these events (or objects), allowing you to repeat any of them (or browse them again) by choosing them from the menu. This gives you an easy way of repeating forms in the Listener, inspecting objects or browsing classes again, revisiting searches, and so on.
The menu lists the last ten unique items to have entered the history list of the active window. Because each entry is unique, some items may have occurred more than ten events ago.
If the editor is the active window, the History > Items submenu lists the buffers currently open.