Popup reference add link breaks node edit form if nodereference is unlimited

To reproduce:

1) create content type
2) add an unlimited nodereference field
3) configure to show popup reference add link
4) create content of this type

For me, the left sidebar gets pushed down. See screenshot.

You will not get this problem if:

1) you set the nodereference field to a set amount (e.g. 10)
or
2) you don't show the popup reference add link