How to delete Primary Entity created by AdvanceCustomizatioWizard after restore default DB file?

Hello everyone. I have create an Entity by AdvanceCustomizationWizard. I also do a backup DB before create this Entity. than I restore the DB and i still see the icon of that Entity exist in Primary Entities. When click on it go to its detail. It has no field, screen, list, tab, .... but i can't delete manually too by go AdvanceCustomization>TablesAndDatabase> click delete on that TableName. Could anybody tell me how can i delete it away ?

Best Regards,

/Sokheng