In MS Office, when you have a document with mailmerge fields (or input fields), 
if you are manually entering the data, MS Office allows you to use "F11" to 
jump the next mailmerge (or input) field (and Shift+F11 to jump back). When it 
jumps to that field it hightlights as well so you just need to type to replace 
it. 

My organization and many others manually process huge volumes of letters and 
use these mailmerge fields as "fill in the blank" based on the customer we're 
dealing with at the time. You obviously can manually mouse/arrow over and then 
highlight the field but it adds a HUGE amount of overhead and makes us less 
productive. It is the only thing preventing us on using Open Office vs MS 
Office.