Thank-you Stephen,
For all "listeners"
To access HTMLeditor manager :
GOTOthe persona bar - site settings / Site behaviour / more - click on the button "Open HTML Editor Manager"
In my case , the wyswig editor was adding a paragraph to HTML code (where there was pargraph spacing).
To solve this :
in HTML editor manager click the editor config tab find AutoParagraph and uncheck it.
You will see there are many other settings that are here
Hope this helps