Yeah menu is visible everywhere. Even if the Menu row somehow got deleted, then you must go in your Helix settings and recreate it.
Troubleshooting is actually easy on that one:
If it is created and one or more menus is not visible, you have to
- Go to Helix Settings, under Navigation and check which Menu is selected to show as default. After that, you have to check if the two menus are under the same Menu Collection or if they are seperated and merge them in one.
- You have to check if any menus are hidden under Link Type settings.
- You have to check if the Language selected in all the Menus is correct.