In the body tab I have unticked the "Show Chapter Numbers in Single Chapter Books". As a result chapter 1 is no longer displayed in the body of the text in any of the single chapter books. However, that number one is still there in the headers. How do I disable that?
Elsewhere in this forum I found "hooks" to take care of this problem. They looked like this:
\setbookhook{start}{PHM}{\global\OmitChapterNumberRHtrue}
\setbookhook{end}{PHM}{\global\OmitChapterNumberRHfalse}
However, they did not work. Chapter one persists in the headers.