There are some hacks here in the form of an extra field "appears_locked_from", which can be used to hint that the user should see the button as locked. Without it, there's some confusion on user side regarding buttons that change states unprompted.
Control and Alt are special in that they aren't expected to switch levels, and so don't need to change what characters are output.
Use in layouts by adding `modifier: Control` or `modifier: Alt` in place of `text: "foo"`.
The latching of the modifier will force the keyboard to emit raw key presses and prevent it from outputting text.
Locking is not determined by button state any more, but rather based on the view active at the moment. If pressing/locking a key results in the current view being active, the key is active. If locking a key results in the current view, the unlock view is activated.
