Correct me if I'm wrong, but at the moment, if you create Tag Group A for exclusive use in Category A, Category A is then unable to use any other tags being used on the site. Is this intentional?
If it is it seems a little odd to me, particularly with how the option is worded Tags that can only be used in this category: or Tags Groups that can only be used in this category:
The way it's actually functioning is:
Tags that can only be used in this category AND Only these Tags can be used in this Category
It should be one or the other in my opinion.
I would like to create a group of Tags that can only be used in Category A. However I don't want that to prevent Category A from being able to use the 20 other tags on the site.
Long term, it would make more sense to have a Tag configuration page that takes care of selecting where the Groups and individual Tags can be used rather than doing it from a Category perspective.
For example select a tag from a drop down list. Say we select tag-a. We then have a page with all categories on the side and the tag at the top. You can then quick select all categories to use tag-a in, or you can individually select which categories to restrict it to by placing a check next to each category. You could do the same with Tag Groups. Granted it might be technically difficult if a tag belongs to a group and they have different settings, but it needs to be properly thought out.
In the short term, wouldn't it make sense to change the behaviour slightly. By default, all Tags should be available in all categories. As soon as a Category sets something on a Tag, the tag and only the tag becomes either:
Only available in this category (and other categories that have it selected). It leaves other Tags unaffected in this Category and all other Categories. In other words the Tag needs to be included wherever you want it available. OR:
Unavailable in this Category. It leaves other Tags unaffected in this Category and all other Categories. If you want to also exclude this Tag from another Category it needs to be explicitly set as unavailable in that Category also.
Interested to hear your thoughts.