As I noted in the bug report, a work-around might be to simply add an extra filter with a different Y Axis as the filters you are actually interested in, e.g., "Print Legend" "Legend" with a Display Filter of "udp.port eq 0" frame.number == 0 or something such as this.this that will always evaluate to false. Then change the color to white so it matches the background color. If you don't even want the word "Legend" to appear in the legend, you can just leave the Graph Name blank.