How can I get value selected in a dropdown inside Datatable


I have a Datatable with rows that allows users edition.

cols = [{"name": i, "id": i} for i in df.columns]
cols[0]["presentation"] = 'dropdown'

return hmml.Div ([dash_table.DataTable(
                            fixed_rows={'headers': True},
                            editable=True )

some of the columns have a dropdown as editable component.
My question is how can I obtain the value selected in a dropdown inside datatable via callback??

PS: I can get all data after a selection using the parameters data and data_previous parameters… so if someone know how the make the diff between them, will help me too.

PS 2: the active_cell parameter don’t return the cell with a dropdown.