[DOCUMENT MAPPING PROBLEM]

I CREATED DOCUMENT WITH "DOCUMENT MAPPING". I SAVE THE DOCUMENT WITH DOCUMENT
MAPPING SHOWING ON LEFT WINDOW OF SCREEN. WHEN I REOPEN THE DOCUMENT THE
SCREEN ON THE LEFT SHOWS THUMBNAILS RATHER THAN DOCUMENT MAPPING. IT DID IT
LAST WEEK, BUT A SETTING HAS CHANGED AND NOW IT NO LONGER AUTOMATICALLY OPENS
UP WITH DOCUMENT MAPPING SHOWING. DO YOU KNOW WHAT SETTING TO USE TO MAKE
SURE THE DOUCMENT OPENS UP WITH DOCUMENT MAPPING VISIBLE IMMEDIATELY RATHER
THAN HAVING TO SET IT TO SHOW. THANK YOU