side question .... why do you need so many different zones?
I'm sorry but I don't understand exactly how you want it to work. Do you want to be able to play in multiple zones simultaneously or not? It would help if you just boil it down to the set of actions you expect to happen in each case. You probably don't need to provide an exhaustive list, just the basic workflow you expect to work is sufficient.
For example
start playback in browser
MC should route WDM input to IPC zone
start playing playlist 1
MC should send to Playlist1 zone
if WDM is active, stop playback
and so on
Having more than just the "IPC" and "General" zones is for the sake of efficiency/convenience. So for example, IPC is strictly for streaming Windows audio (web videos, external media player, OS notification sounds, etc.). Then I might have a zone specifically for smartlists of songs I haven't rated/edited meta tags yet. Another zone might be specifically for smartlists of songs within a certain time period of import, and I'm going through them to build specific playlists for specific purposes (for driving, writing, sleeping, etc.). There could be also zones dedicated to specific playlists. Having these zones means whatever I'm working on at the moment (editing meta tags, ratings, creating playlists) in that zone won't just get cleared out and replaced whenever I play a track from another list/location or whatever. I could switch between zones and resume exactly where I left off, instead of having to go and hunt down the specific smartlists or playlists and then try to find where in the cue I was before. I can have multiple zones all contain work-in-progress stuff that will keep exactly where I was.
As for what I'd like to be able to do, I'm actually okay with the zones that start playing to not stop other zones that are already playing, as it's not that big of a deal to manually stop a zone that's playing so they don't overlap each other's audio. It's also good to have IPC zone to never be silenced because some notification sounds could be very important. Originally I wanted to be able to have any zone that starts playing to automatically stop other zones that are already playing, just so I don't have to do it manually (such as I'm listening to music, but see a web video I'm interested in and I click on it to play, and it just overlaps the music I'm already playing), but honestly that's really not important so as long as I can automatically route IPC and specific lists to separate zones, I'm good. Which means I'm fine with what I'm able to accomplish with zone switching as is--not need for more (unless I think of something else I'd like to be able to do in the future).
I'm also a little confused about exactly what OP's goals are, but he
may be running into one of the little "quirks" of using zoneswitch
with the IPC, which is that the IPC input zone will *never* actually
stop playback in the other zones when IPC input starts. This is (as I
recall) by design, because if the opposite were true, every system
sound, autoplay ad, or other background PC noise would be interrupting
normal playback constantly (because the IPC zone can't distinguish
between intentional and unintentional activity on the system soundcard)
Yes, I agree, as I stated above. Some notification sounds are important and shouldn't be silenced, and they also shouldn't constantly stopping other zones that are playing as that would get annoying.