The first letter in the main branch is always capitalized and I have not found a place to influence this. This is not a problem for other sub-branches, I set this via the options. Is there a solution for this?
Right-click on a topic and choose "Format Topic". The "Text and Capitalization" tab controls the capitalisation. You can apply changes to the default topic theme, or if you edit the template it will apply to all future maps using that template.