Here is a nightmare scenario in Enterprise Architect. You created a Tag Definition that points to elements in your models. After being used for a while, you realize that the name of the Tag Definition is confusing, so you change it to something more appropriate. Now, all of the tags that have already been created do not match the Tag Definition and are orphans. Instead of seeing the element to which they should point, all you see is a GUID.

If you had managed this change in Model Guardian, this would not have happened. But even if you have done this outside of Model Guardian's safety net, you are still okay. Simply use the Change Tag Name form to rename all those old tags to the new definition and all the model elements will reappear in your tags.