Why does this geometry say "Nothing selected"? I'm modelling a character that is all one mesh.

When I select the body of the character, I'm able to move it around, but when I select the pants, I can't move them.

I've also noted that the Item menu says &quot;Nothing selected&quot; when the pants are selected. What's wrong here?
I found the issue! Somehow I managed to hide all the vertices without hiding any faces. Unhiding everything with Alt + H fixed the issue for me.