Option 1

If you are looking for an alternative (also works on taskbar)

This software is fairly old but last I checked still worked.

http://www.chrisnsoft.com/standalonestack

Option 2

There is also this program that allows you to assign a folder as a menu, albeit you need to create a shortcut to the exe and add the folder to the end of the target field.

https://ramensoftware.com/quick-folder-menu

Option 3

Final option works the same as the above one but with start11 2.0. When you pin a foldermenu with start11, you can navigate to its stored location and copy that shortcut to your dock. To do this create a shortcut on your desktop and put this in the target field. Once filled out hit ok and drag onto your dock.

"C:\Program Files (x86)\Stardock\Start11\PinMenu.exe" "E:\Desktop"

& in start in

"C:\Program Files (x86)\Stardock\Start11"

Hopefully one of these helps you out!