Of course the last step is that you have to actually now *select* this new theme:
Open Settings->Appearance->Icons. Choose the theme with the name you gave it. For me that was: "elementary Xubuntu dark - with nm-device-wired-secure".
Now that will work. If there is ever an update to the xubuntu-icon-theme package (containing /usr/share/icons/elementaryXubuntu/), you'll need to repeat these steps.
Aarrrhh, forgot something in my last comment:
Of course the last step is that you have to actually now *select* this new theme:
Open Settings- >Appearance- >Icons. Choose the theme with the name you gave it. For me that was: "elementary Xubuntu dark - with nm-device- wired-secure" .
Now that will work. If there is ever an update to the xubuntu-icon-theme package (containing /usr/share/ icons/elementar yXubuntu/ ), you'll need to repeat these steps.