Main function does not work for multi track rectangular manhattan plot

[Lloyd-wubo]

Hi Lilin,

Thanks for developing this wonderful tool. I was wondering how the main function should be used when plotting a multi-track rectangular Manhattan plot (multracks=TRUE, plot.type="m", type="p"). In previous issues, you mentioned the main parameter should be a list for multiple traits. I have set main = list("Test1", "Test2", "Test3"), but no title was printed for any trait. Could you please check if there's anything wrong?

Thanks,
Lloyd