KeyboardNavigation cannot set up navigation to children of Repeater that don't yet exist

When Repeater used for Item creation,
we have following issue:

When Repeater create new item and this item tried to
use keyboard.left or keyboard.right to other Repeater's item -
these items don't create yet, and we have issue with
navigation keys.

Set rightSet to true if right really changed.
When object call KeboardNavigation::setRight with null item.
rightSet field = true, but right field did not changed (null).
After that navigation keys works incorrect.
The same for other cases.