Currently, the 'Insert Mail Merge Field' window must be closed after a field
is inserted, and before you can insert another one.  The box should remain
open to  allow the user to insert a merge field, then to click on the next
location within the document, then to click on the next merge field to be
inserted, and so on.

Having to click 'Close' then reopen the Insert Field window when the user
needs to insert muliple fields into a document is irritating and a waste of
time.