Alt + ←
Explorer++ maintains a list of previous locations, or history, for each tab. The Back (and Forward) items on the Go menu can walk through this history, much like hyperlinks in HTML browsers (eg. Mozilla Firefox).
Back returns the currently active tab to an older location, closest to the current location in the history. If this item is disabled, the Files pane (active tab) is displaying the oldest location in the history, the location when the tab was first created, or when Explorer++ was first opened.
A tab’s history can be thought of as a collection (or list) of locations in the order they were visited, with the oldest at one end, and newest at the other. Locations are added to history each time a location is visited by
clicking on a drive in the Drives toolbar,
clicking on a folder (or other item) in the Folders pane,
double-clicking (or single click, with Single click option enabled) on a folder in the Files pane,
clicking on an item from the Go menu, except Back or Forward,
clicking on the Up button on the Main toolbar (same function as on the Go menu), or
entering an address in the Address bar which changes the location.
Executing Back or Forward simply walks the Files pane through the current history for a tab; the functions do not add to, or subtract from, the location history. It is possible that history locations may be duplicated, if they were visited by one of the above methods more than once. As Back or Forward is used (either from the Go menu or the Main toolbar), items in history are re-distributed between the Back history and Forward history; Explorer++ maintains histories in both directions.