This drop down combo is visible when the "Method" buttons are
(Implode) and (Implode) and the action is equal to where-used
replacement of a component.
It refers to the number of the component to be replaced by the component
in the "Replaced By Component" field. It is populated with all Part Numbers,
Descriptions, Source, Fixed Account and Serial/Lot Control from the Part Master table.
The number of characters to be entered before the list is shown is governed
by the value of "populate length" (mandatory).