This dialog is used to view a history of the most recent actions that you have performed, and provides you with the opportunity to undo or redo one or more of these actions. At present the action history will retain the last 16 actions you have performed. To access this dialog, click 
from the Quick Access toolbar.
Note: To select multiple actions, simply click on a entry higher (or lower if you are selecting actions to Redo) in the list and all actions in between will automatically be selected.