This lets you do manual zoning quickly when you want to process only parts of a page, for instance to select only certain paragraphs and diagrams from an article.
Make sure the Select zone tool is active.
Move the cursor over the page image. Shaded areas will appear one after the other, showing the auto-detected zones.
Double-click in a shaded area to transform it to a zone.
Repeat as desired, checking that zone types and boundaries are suitable and modifying them if necessary.
Send the page to recognition. The zoned areas will be processed, everything else will be ignored.
If the the On-the-fly tool is on then the zone is recognized immediately.