By default, filtering is on and only records in the current search are visible. When filtering is switched off, all records in Great Domesday are visible and available for browsing. With filtering off, records in the hit list are indicated in the following way:

text hits are in the default font and other records are greyed out
table hits are in bold and other records are greyed out
facsimile hits are boxed by a bold blue line, other records by a faint line
map hits are in red, other records in grey.

Filtering may be toggled on and off from the Window menu or the Toolbar.

For more information on searching, see 
Searching Domesday Book.