Hi @Anil_G and thanks for the response.
Drawing a box with mouse pointer around the red circled signature of the first post, does not appare the dotted red box and the relative pop-up to link to a field.
This signature IS NOT pre-annotated by the engine.
Drawing a box with mouse pointer around the green circled signature of the first post is possible to draw a box to link to the field.
This signature IS pre-annotated by the engine,
The document is only of one type, a structured one with ten page, with two to three signatures on page one, two to four signatures on page two and one to two signatures on page nine.
Composing the data set (fields) with the first uploaded document, i generated all of nine fields for all possible signatures, with a sample document in which the all nine signatures are present (not all signatures are always present in the real documents).
Any thougs?