Unable to access Navigation menu component sub menus

Our dev team is developing a WinUI3 tool (using C#) and I need to access the File & Tool submenus - see screen captures.

The File menu has Open, Save & Exit items.

The Tools menu has Build & Export Report items.

Looking at the TestComplete screen capture, I can see and access the File, Tool & Help menus but not their submenus.

How can this be achieved?