Scriptwriting mode | drop-down menu containing the various elements for the selected format

This menue is supposed to have full keyboard access being called up with “Ctrl-” at any time from
within a scriptwriting document to select an individual element style by tapping the associated letter for it, on the right side of the menu.

I do not know how to exactly effect the desired result. Do I have to press “Ctrl” or - aditionally - “-” to make the menu popp up? If press just “Ctrl” - nothing happens. No parentheticals appear if I press, for example, “Ctrl-P”.

What can I do to enable the keyboard access?