Be careful when editing web pages using editors that autoformat the underlying HTML.
For example, the FCK Editor version on Nexedi ERP5 (outdated) will line breaks
added in the HTML content, so text blocks and also code snippets will be
reduced to a single line.
Other editors are OK, but you should prefer a raw text editor to write in HTML
to have maintainable text — it will help you a lot when you will have to
update your page.