- Add a sync table to pack (with no featured properties)
- Configure it, and sync so that there are some rows in the table
- Manually add another column to the table that is one of the properties of the table items, say “MyProp”
- Hover over an item in the table (its chip), and click the “Add Column” button for the “MyProp” property.
- It is added again to the table.
This seems inconsistent with the behaviour when the “Add Column” button is clicked, where it switches to show “Added” and is no longer clickable.