When SCROLL is set on, this will allow you to scroll back through your lastlog entries 1/2 page at a time. The default binding for this is meta1-p. A key must be bound to SCROLL_END to exit this (default meta1-e). It is suggested that you have HOLD_MODE set on or otherwise when you get out of the history all your new messages will flash by.
See Also: bind/scroll_forward bind/scroll_end bind/scroll_start