I have seen in many places that users of Xfce they have asked how to open the application menu using a keyboard shortcut, and in many cases they have received no response.
En Gnome 2 we can do it by default with [Alt] + [F1] and in Xfce We can also do it, with the combination we want. It is very simple. For this we will Menu »Preferences» Keyboard »Applications Shortcut. We add a new shortcut and put as command:
Then we assign the key we want, in my case, I put the typical key with the Windows flag, best known in the world GNU / Linux Be Super L.