The DM_LISTGETDATA message is sent to the dialog manager to retrieve data associated with an item in a
DI_COMBOBOX or DI_LISTBOX list.
Param1
The ID of the dialog item for which the item data is retrieved.
Param2
Index of the item for which the data is retrieved.
Return
Data value the plugin has associated with the list item using
DM_LISTSETDATA message or NULL if no data was associated.
See notes for FarListItemData structure for more details about data storing logic.