Groups evolve into categories or tags and items can be added to multiple groups
To summarize, I'd like to have permanent groups that don't "leak" items, like profession or material groups, and also temporary groups, like selling lists or sales groups, which I can just delete altogether & start new temporary ones instead easily from the new items in my bags (which again may exist in permanent groups). And obviously those two types of groups must sometimes overlap, as an item can belong to a profession (and shouldn't be removed from it) and also belong to a current sales list (to be removed from it once sold). And I do hope that we can think outside the box, pun intended, and have our boxes evolve into categories or tags, because we ain't dealing with physical goods anyway but virtual ones. So, instead of thinking of TSM groups as physical boxes, we can think of a TSM group as a tag, category, or attribute. And there's absolutely no problem with one programming object acquiring multiple tags or attributes, some permanent and some temporary and fleeting. I hope the devs can consider this feedback. And if there's some sort of genius way to accomplish the goals I detailed above using the current system in an automated, time-efficient way after setting things up once, which is what I expect from TSM at this point, I'm happy to hear about it. Thanks.
For example, I have a large group for all the herbs in the game, which I use to easily mail any herbs from any alt to the character that uses them for alchemy, inscription, whatever (thus this huge permanent group is attached to a mailing operation), so I'd like that group to stay as it is and be a "permanent" group; on the other hand, perhaps I'm done using a specific few herbs for any reason, ran out of space or whatever, so I'd like to start selling those herbs, and thus I'd like to add specifically those herbs to my constantly changing "sales list" group, which is attached to an auctioning operation.
Now, obviously I do not want my huge herbs list to suddenly be missing a few herbs, because I'd rather not constantly import such huge groups; this would be a repetitive task that is against the whole spirit of TSM automating and speeding up repetitive, boring tasks for us. Besides, I gave just one example as, well, an example, but this can be applied on multiple other groups, professions, etc., which I'd have to keep re-importing. Yeah, I'd rather not have to do this. At the same time, I'd just rather not be forced to keep manually checking my ever-changing "sales list" group for the specific items that I need to remove and place back into their "permanent" group. Once I'm done with most of the items in a sales-list group, I'd like to delete the group in one go and restart another group for any new items that I'm selling.
Accordingly, as far as I can see, I do need the ability to add items into more than one group. Or perhaps to put it more programmatically, I need pointers that I can place in temporary groups, which point to items in permanent groups. The items remain in the permanent groups, and the pointers can safely be deleted with the temp groups.
I have a different need from branching groups. I need a group for herbs, for example, and another group for sales. The sales group will be constantly changing, but the herb group needs to be constant or never have any item from it disappear; it's like a "professions" group, for example.
Another major problem I'm having with the current design is that when the items I want to sell are in my bags, I cannot even easily add them to the sales group if those items already exist in one of my intricately designed branching groups. So, yes, I'm actually using that sub-group system very well. I'm using it well-enough to feel very stressed when it seems that I have to break those well-designed group trees, the "permanent" ones, in order to be able to add what's in my bag to a temporary sales group.
And another problem with the current design is that sometimes I don't even know in which group the items in my bags exist, because there isn't a way to search for an item in all my groups, unless I have to be forced to use literally one group for the whole addon and everything else becomes a sub-group of that mother of all groups, and I don't even know if such a system would lag the game/addon hopelessly or not. I also would really prefer to not have a mother of all groups and everything else starts to branch from that. However, the bigger problem is that I cannot add the items in my bags to a selling list/group if these items already exist in a permanent professions/mats group, [and] I do not want to remove those items from that permanent professions group, or otherwise it won't really be "permanent," if you see what I mean.
And I discussed this on your Discord and didn't really receive any convincing answers. So, yes, I do believe that TSM groups should evolve into categories or tags, while still keeping their current label as "Groups" so as not to confuse the many existing users of the addon.