Help using filter option

I hit F3 to bring up the filter box.
I type in wolf
It shows me 4 results
3 Artists which contain wolf
1 Titles which contains wolf

I only want artists that contain wolf so I click the triangle button next to the end of the filter box and a drop down menu appears and I select artist

The filter box now contains:

but now there are no results showing?

What am I doing wrong?

Thanks for help

You don't read the help file:

artist HAS wolf