Installation: Simply copy the Step&Repeat XT to your Quark XTensions folder and relaunch Quark.
Use: Step&Repeat XT attaches a pop-up menu to Item->Step and Repeat. This new menu will list the last used Step and Repeat horizontal and vertical values. The default Step and Repeat values pair will always be checkmarked.
Select one of the menu items and the pair of values will be used for the next Step and Repeat (also for Duplicate). Entering new values in the Step and Repeat dialog will automatically add a new item to the pop-up menu.
To delete a menu item, select it while holding down the shift key. Hold down both the shift and command keys to delete all of the items from the selected one downwards. (Note that the current default Step and Repeat values pair cannot be removed).