Using Word 2003.

Say I'm entering merge fields for an inside address on a letter, I click on
the "Insert Merge Fields" tool and I then click on the merge field I want
inserted. Unless I close the merge fields selection box, I am unable to do
anything in my letter, like press [enter] to go to the next line of the
address so that I can enter another merge field. Which means I have to add a
merge field, close the box, move to the next line of the address, open the
merge fields tools, select the next merge field, close the window, etc.

This can't be right, can it?

Using the address block option doesn't allow for the addition of the
addressee's title or position.