The Manual indicator on the Components page helps you to know which specification items have been manually created or edited.
The Manual indicator for a filter line is set when you change data for spec items belonging to that filter line and then click Save above the Spec Items grid.
When you click Generate, the software does not consider the filter lines with the Manual indicator set. The software only considers the filter lines with the Manual indicator cleared. Previously-saved spec items are kept.
If you clear a Manual indicator and then click Generate, the software deletes the spec items for that filter line, and new spec items for that filter line are generated.