nm-applet has disappeared on an xubuntu 22.04 system

[Chris Green]

My wife runs xubuntu 22.04 on a ThinkPad X201 and, just a short while
ago, the nm-applet icon disappeared from the panel.

I've managed to get a wifi connection up and running using nmcli but
we need nm-applet back!

The program is running (nm-applet that is) but nothing appears in the
panel.  

Can anyone suggest what might be wrong and/or how to fix it please.

-- 
Chris Green