Trapping Category The Trapping category offers you a way to ensure that your document’s trapping values are desirable and is split into Text, Background and Frame controls. Text Controls Check any of the Text trapping boxes for FlightCheck to alert you when the document has been set for trapping text characters. Background Controls Check any of the Fill trapping boxes for FlightCheck to alert you when an object on the document page has been set for background trapping. Frame/Line Controls Check any of the Frame trapping boxes for FlightCheck to alert you when an object’s frame or border has been set for trapping.