The Tab is used with all records. It shows you a complete listing of all the data that you have for the current record, in a hierarchical layout. This is exactly the same layout that is used in the Records Window. It also shows the record id, and the last updated date.
You can if you wish edit almost any aspect of a record in the All tab. The technique is the same as that used when editing records in the Records Window. Right-click on a field name (left column) to bring up a context menu with 'Add' commands for each of the sub-fields which you can validly add to that field. Alternatively, to delete a field, select it and press the Delete key. If you want to edit the value of a field, click on its current value in the right-column.
To change the order a field with respect to its sibling fields where
this is permitted (which it isn't always), select the field and click
the Move Up
or
Move Down
arrow buttons, in the top-right corner of the listing.
Where a record contains links to other records, the name of the linked
record is shown in the right column with a little white check box
to the left of the record icon.
Check this check box if you want to see details of the linked
record. If that record in turn links to other records, you can
follow their links in the same way. And so on, indefinitely.