How to reproduce:

1. Open HUB;
2. Create a new project;
3. In the "Hierarchy" window add some object;
4. Go to "Inspector" window and find "Tag" section;
5. Verify, that by default it shows "Untagged";
6. Click the dropdown arrow and select "Add Tag";
7. Verify, that "Tags & Layers" section should become displayed and "-" (removing option) is disabled;
8. Click on "+", enter new tag name and click "Save";
9. Verify, that tag becomes displayed in the list;
10. In the same way create few other tags;
11. Verify, that all newly created tags are displayed in the list and "-"  (removing option) is active even none tag is selected in the list;
12. Click "-" (remove option);

 
Expected Result: If tag is not selected, remove option should be disabled. And only when tag is selected remove option should become active. Unity documentation
Actual Result:  Remove option is active always.

Reproducible with: 2021.3.0f1, 2021.3.11f1, 2022.1.18f1, 2022.2.0b9, 2023.1.0a12.
Not reproducible with: 2020.3.40f1.