A liquid dispenser cassette includes a frame, dispense head assemblies, and a one-piece integrated slot extender. The frame defines openings. The dispense head assemblies are mounted on the frame. The dispense head assemblies include dispense head dies at least partially exposed through the corresponding openings. The dispense head dies defines top slots. The slot extender is mounted on the dispense head assemblies. The slot extender has reservoirs defining drain openings mated to the corresponding top slots.