* Items in tables that, when edited or added, were previously expanding the table should be replaced by a popup.
* No part of the popup should be inaccessible — if larger than the viewport, we should be able to scroll.
* The popup should automatically scroll to show any errors that appear.
* It shouldn't be possible to interact with the page behind the popup, without closing the popup first.
* It should always be possible to close the popup.
* The title of the popup should properly reflect its contents.