I checked the output and even if I only choose <section id="sp-main-body"> to replace nothing happens.
I had a look at the plugin order but couldn't find something that is not correct.
I found out that if I search for <section id="sp-main-body" > than the rule works. So it seems that something cleans the html output.
Maybe you have an idea where I can look for the HTML code before cleaning?
I have looked at the system plugins and the only thing that might do that is JCH Optimize, but if I switch it off the HTML Code stays the same.
thank you for having a look. This works now.
Can you tell me why it worked in Joomla 3?
There I just wrote: <section id="sp-main-body"><div class="container"><div class="container-inner"> and everything worked.