Hi Gao,
Which you get depends on your Transition Settings - Full-Scan settings. If you have None chosen in this tab, you will get concurrent transitions. If you have something else chosen, then you are telling Skyline you are not doing SRM, and you will get concurrent precursors. I suppose it may still be interesting to be able to switch back and forth regardless of your Full-Scan settings, but hopefully, this is enough to get you what you are looking for without needing a new feature in the software. We have not removed anything in this area from Skyline.
Thanks for using Skyline and posting to the support board.
--Brendan