Insertion Mode

Determines whether a value that the user enters is inserted into the list of predefined items, and if so, whether it must be unique. One of None (default), Unique, Always.

Value	Description
None (Default)	No entries are added to the list.
Unique	The input should only be added if the entry is unique (ignoring case).
Always	The entry should be added regardless of whether or not it is unique. This setting is useful when using a combo box as a history list.