Quick Keys and Menus

If I use the menus to get to Toggle rhythmic slash notation : A of slash is underlined, so It should be accessible ..
but I do not know how ( maybe it is a 14 error... 14 inches in front of the screen.)

I do Alt T (accesses the tools menu) , alt- a Gives the transpose menu, instead of toggle slash....
if I do Alt T, then A nothing,, control a etc... does not work.

I did a shortcut keys control alt R , to access it ...
thanks.