When pressing the "Menu" key, pretend a right-click happened and show the containment context menu.

FolderView eats the key event so far but on Desktop works.

It works for both the regular context menu as well as if you have set it to show application launcher.

It doesn't trigger the applet's context menu, however, but the only applets that can get focus are stuff like folder view and notes. Applets could still intercept it (in fact, FolderView has commented code that is supposed to do this, will have a look at this) and do their own thing. Only if the event isn't accepted it will propagate all the way to the containment and trigger the menu.