Hello Gareth,
Thanks for your response.
Thanks for your response.
I think it turned out to be a problem of the plugin installation: in the middle of changing the toggle background color later, the entire site suddenly hanged up. I had to log back in after that. Then the option of "Collapsible Topic Format" completely disappeared from the course format option dropdown list. Strangely, the regular Moodle core Topic format kept the collapsible feature and can collapse and expand.
I then reinstalled the Collapsible Topic plugin. This time everything worked, including the display of section 0. I can now see everything inside of section 0 (general section), as well as all other sections after it, on the course homepage.
I then reinstalled the Collapsible Topic plugin. This time everything worked, including the display of section 0. I can now see everything inside of section 0 (general section), as well as all other sections after it, on the course homepage.