Insert labels no Audacity 3.0.2

Hello everybody!

The “Add
Current Selection Label” is disabled, as well as the Ctrl M shortcut does not work as shown in the attached image.
Can a friend tell me if there is any configuration in Audacity for this option to be enabled again, or am I performing some wrong or incorrect procedure?

Note. For educational reasons, I am still using version 3.0.2

Thank you very much!

Att,
Marcos
Audacity - Rótulos