No, there's not a way to exclude a business object from showing up in the BOMapper. You can leave the business object unconfigured (with the little red x) and when you do a Rebuild All, you'll get an error in the results telling you that the business object was unconfigured, but you can ignore it.However, if you want to exclude a business object from showing up within the type editors such as the ComboBox's PopulationDataSourceSettings and such, you can add the MicroFour.StrataFrame.Extensibility.HideFromExtensibilityAttribute() to the busines object class.