Adding existing datasets to organizations is broken

[seanh]

On the organization read page there is only an 'Add Dataset' button, not a drop-down with add new dataset or add existing dataset as on the default group page.

On the organization edit page you do have the drop-down, but if you click add existing dataset nothing happens except it appends #datasets to the URL

[ross]

Add existing dataset doesn't make a lot of sense because they can only belong to a single organization. Best would be to fix the organisation template to remove Add Existing.