Yeah I had that as well when using the machine on its own before.
Just throwing an idea but for example an extra “lock” icon left to the tempo field could be nice.
With the addition of a shortcut to achieve this. For example, shift+tempo+F8 or F9. Or just tempo +F8 or F9. Or the contrary F8 or F9 + tempo. (whatever would work best)
F8 or F9 being used to lock stuff on the machine.
It would show the popup screen below with the “lock” icon on the left of the tempo instead of the 3 horizontal bars 
