Expression map sound slot lane visibility limitation

for sure thats all good information in general mducharme when it comes to expression maps. So far in Halion with any orchestrations I’ve encountered I have not been able to use add ons in the way you describe, so for me right now, it just seems like the same amount of work to add a slot or an add on. The main advantage for the add on in these simpler scenarios seems mainly that it auto creates another group for you.
but I appreciate all your effort to just put forth your experience in general.

If and when you create your YouTube video on the subject hopefully come back and share your link…

@andy1324 please share a project file that contains the current state of what you’re trying to do.

Just to summarise a couple of key points that Michael mentioned before (thanks!):
If you want to play mute+string4 at the same time, you’ll need to create a single slot that contains both articulations (which need to be in different groups). Alternatively, string4 can be defined as an individual add-on slot, in which case it should automatically form a combined slot at playback time.

With all of this, it’s important to double check what the instrument receives, separately from what the sound slot lane indicates. I wouldn’t rule out that there is unexpected behaviour or a bug lurking in either of them - in which case we need to work out exactly where exactly the problem shows up. It’s more likely that the sound slot lane is missing some information, but the playback is correct.

as far as the slot lane goes, (when using multiple groups) it appears Priority is given to group 1 visually. Group 2 articulations can be seen, but only if there are no Group 1 articulations blocking them. No extra info is given on mouse over. The lane only allows viewing of 1 articulation at a time.

One thing that came up in this thread is something I already suspected might be the case, that add-on slots are not currently being reflected in the sound slots lane (via tooltip). The similar lane in Dorico will show the add-on slots being applied in the tooltip.

Ah yes, I think that is the problem here. I’ve logged this now. CAN-63600