Alt + →
Explorer++ maintains a list of previous locations, or history, for each tab. The Forward (and Back) items on the Go menu can walk through this history, much like hyperlinks in HTML browsers (eg. Mozilla Firefox).
Forward returns the currently active tab to a newer location, closest to the current location in the history. If this item is disabled, the Files pane (active tab) is displaying the newest location in the history.
See here for a more detailed explanation of a tab’s history.