You have opened the Properties <...> dialog for a device (for example by double-clicking on the device in the graphical editor), clicked [...] in the Part number field on the Parts tab, or in the Part selection - <Parts database> dialog you have clicked [...] in the Automatic filter field.
In this dialog, you can specify which properties of the selected device should be used as filter criteria for part selection. Only those values are compared which are specified in parts management.
Overview of the main dialog elements:
Function definition:
Trade:
Macro:
Select these check boxes so that only those parts will be offered which have the same function definition / trade / macro as the device selected.
See also