I think I may have found a possible bug in Page Headers. Here’s my repro…
1. Create a page header
2. Assign it to Global Locations -> Post Types – Single -> Pages
3. Create a new page and verify that the page header shows up
4. Delete the page header from Page Headers -> All Page Headers
At this stage I would expect the page header to not be visible when the page in step 3 is refreshed – but it is.
Note that if I look under Global Locations -> Post Types – Single -> Pages the header in question is no longer listed, but it actually still active (even though it was deleted in step 4 above).
If I manually change Global Locations -> Post Types – Single -> Pages to the empty (first selection) and save, this does indeed result in the page header being truly removed.
Because Post Types – Single -> Pages shows nothing after step 4, I assumed it had been properly deleted and took me a while troubleshoot this. But I had to manually select the empty option and save to get the page header to really disappear.