Will & Grace (1998) - 4x23 - Fagel Attraction

After his laptop computer is stolen, Will meets a sociable police detective who takes a special interest in his case as they go undercover – but Will doesn't know that the gumshoe is secretly participating in Jack's therapy group for gays. Elsewhere, Grace is again hassled by her psycho neighbor Val who "opens" a rival design business and prospers by stealing Grace's ideas.