labels for transitions in composite states are in the background

[Reissner]

Although it is possible to draw transitions of states in a compound state,
it is not possible to endow them with labels: in fact, the label may be drawn but is "behind" the compound state.

A bit similar behave notes which are also hidden by composite states.
I feel, a concept of layer is missing: composite states shall be in the background.
The layers can be computed by the containment tree(s).