Numbering ON/OFF assigend to short cut key ctrl+shift+N does not work

I want to use the short cut key ctrl+shift+N to switch Numbering ON/OFF. However, nothing happens when doing ctrl+shift+N

I did:

Click Toolbar / Customize
click tab Keyboard
click into Shortcut key window
to ctrl+shift+N => nothing was assigned
select Catagory: Numbering
select Command: Numbering ON/OFF
click Modify => Numbering ON/OFF is assigned to ctrl+shift+N

do ctrl+shift+N nothing happens
but do ctrl+shift+B works and starts / stops a bullet list

close LibO and restart => no difference

Why is ctrl+shift+ B (bullet list on/off) working and ctrl+shift+N (numbering on/off) is not working?

Thanks I advance for help!

LibO4.0.4.2 / XP

(1) Please consider that Ctrl+Shift+N is the LibreOffice shortcut key for

New Document From Template (Template Manager).

(2) You should use the second function Numbering On/Off

(see screenshot):

That works for me with the shortcut keys

F12 (default),

Ctrl+Shift+N,

Ctrl+Shift+M.

Selection of the second Numbering On/Off is a bit tricky! Thanks for this hint.

Why there are 2 functions Numbering On/Off? A special purpose ro a bug?