Sometimes Handset Designer cannot place formwork that can accommodate ties. This happens most often in odd corners. To help strengthen these situations, Handset Designer inserts an engineered brace,which appears as a yellow rectangle attached to the formwork and signifies that additional design work is needed at this location. It is the responsibility of the designer (and of the end user of the drawings) to further design this brace to ensure structural integrity. Usually you will only see this brace inserted over a Job Built Filler (JBF).