Upon clicking this icon, you will see two lists, one of them names the last 20 cards that you have looked at, another shows all of the cards you have marked for review. Clicking on any name will move you to that card. The recent list is automatically updated as you work, the marked card list contains only the card you chose to mark. You can remove cards from this list by holding down the "option" key while clicking on the name of each offending card. Alternately you may clear the entire marked card list by clicking on the "clear all" button at the center of the screen. See the discussion of the Mark icon for more information.
