There should probably be a warning in the docs about MUI_CUSTOMFUNCTION_MOUSEOVERSECTION not getting called if you are not using the DESCRIPTION macros, so either check for the define and call the function no matter what or tell the user to use .onMouseOverSection. Also, the docs call it MUI_CUSTOMFUNCTION_MOUSEOVERSECTION and not MUI_CUSTOMFUNCTION_ONMOUSEOVERSECTION
Thanks, fixed. I only fixed the documentation because of the way description macros are built.