I stand corrected, my desk top version automatically shows all the notebooks where the item is found before I even finish typing, and the mobile app for some reason shows only one notebook until I hit the search key (magnifying glass), then all notebooks where the search term was found suddenly appear. This behavior along with this topic content made me jump to an incorrect conclusion.
Apologies, the mobile app does indeed search all notebooks AND all content inside notebooks just as the desktop version does as far as I can tell.
Regards, Jay