<Binding key="Tab" action="StepEditing/insert-rest"/>
<Binding key="Primary-Tab" action="StepEditing/insert-snap-rest"/>
+ <Binding key="BackSpace" action="StepEditing/back"/>
<Binding key="z" action="StepEditing/note-velocity-ppp"/>
<Binding key="x" action="StepEditing/note-velocity-pp"/>