We will be putting out another update soon (23.0.1.2). I added some code that, for the auto-generated Slick-C tag files, Auto-tag or Rebuild Tag File will always rebuild the tag file, tagging the macros for whatever installation of SlickEdit you are currently running. Also, Slick-C tagging operations like find-proc will check your current tag file and if it does not have macros from your current installation present, it will rebuild the tag file for your current installation.
This is the way it will work moving forward, older version are, of course, going to continue to do what older versions did.
Tools > Tag Files... will always include Slick-C tag files, unless you have just started with a default configuration and have no Slick-C tag files. Sometimes it gets a bit lost in the list if you work with enough different languages, but it is there.