I have some documents for a customer that have a code in
them to insert the total number of pages in the document.

Some of these documents update the field automatically
whenever the length of the document changes.  Others don't
update it until I right-click on the area and ask it to
update.  I cannot for the life of me figure out what the
difference is between these documents.  I've tried pasting
that area from a document that DOES update automatically
into a document that doesn't, and that doesn't work, so it
must be a code or preference in the document as a whole.

I know I can tell it to update the fields automatically
when it prints, but I'd like it to do it while I'm editing
as well.  Possible?