Smart Duplication allows you to quickly duplicate objects vertically or horizontally, and control the spacing between them.
To start, click on the Smart Duplicate button on the selector tool toolbar to enable the handles:
Afterwards, click and drag the + handles either side or below the object to duplicate in that direction.
You can drag towards the original object to also remove copies.
Use the spacing handle to control the spacing between the shapes
Hold shift when dragging the spacing handle to resize from the centre.
Some objects can't be duplicated using the Smart Duplication handles for technical reasons. If so they will not appear when you select the object with the option turned on. When this occurs, you can still duplicate the object by holding the right mouse button and dragging, or copy (Ctrl + C) and pasting (Ctrl + V).
Groups are treated as one object when duplicating.
Objects must be aligned next to each other in order for the handles to appear. Xara will duplicate up to 2 alternating objects however, so you can have 2 axis on which to align your objects against. In the below example, Smart Duplication will work for both the top and bottom sets of objects:
If one object is out of alignment however, then the handles will not show: