Stupid Question about custom header not showing up

[~Jan~]

In one of my proof galleries, my custom header is not showing up. I'm sure it's a very easy fix, but I can't figure it out!! :dunno

[Allen]

In one of my proof galleries, my custom header is not showing up. I'm sure it's a very easy fix, but I can't figure it out!! :dunno
Make sure "custom" is checked for appearance under customize gallery and
hide owner is not checked.

[~Jan~]

THANKS! :clap