NodeList HTMLContentElements.distributed

if you add an item to distributed that is already in the distributed of a younger tree or higher in tree, it is not rendered (render only once). How is this accomplished?

The rendering algo could account for things that have already been rendered, thus letting duplicate items be stored in the various insertion points' distributions.

However, the problem here is that now you have no idea (looking at the insertion point) whether any given item renders or not.

Thus, we have to eject or reject items added to "distributed".

In case of "first one wins", we reject additions (throw exception?)
In case of "last one wins", we eject previously added items (event?)

Is the list dynamic or static?
If it is a static list, it's better to make this a method instead of attribute.
I don't think attribute + static list follows Web API norm.

These are old ideas that haven't panned out.