"Git" -> "Current File" disabled for project in /tmp

1. Create a new Qt Widget Application in directory "/tmp" using "File" -> "New File or Project..."
2. On the last page of the wizard, select "Add to version control": "Git" and click "Finish".
   Creator creates a new Git repository and stages the new files.
3. Open one of the files of the project.
4. Open Menu "Tools" -> "Git".
   Submenu "Current File" is disabled. Keyboard shortcuts to these features don't work either.

I don't see a valid reason why this submenu is disabled. If there is one, please explain.
When you create the project in your home directory, the submenu is enabled.