Control + D

If I select an object (lets say a circle), then [NumericKey + ] to duplicate it, grab and drag some distance to the right, this moves the duplicate to the right, then press Ctrl+D, sometimes it duplicates the circle and moves the new copy to exactly the same distance to the right.  So, many Ctrl+D makes many copies to the right of the last one.  Imagine duplicating pins in a connector.   But sometimes when pressing Ctrl+D is asks me the distance to move, and I can't make it repeat the last copy / drag / paste.  Why is that?   CorelDraw X7.