This is incredibly confusing. Could you explain what the “@” means and how to use it? I have seen it in the Kanban Settings UI and could not figure out what it does.
Also, why is having a custom “@” makes it impossible to use the dropdown? Just add the “@” entry to the dropdown, wouldn’t that work? And even better, why name it the “@”? Say “All Categories” in that dropdown, and make it use the “@” behind the scenes. It turned out to be too cryptic even for me, a software developer, who’s been also using Discourse from its inception.