When an article consists of different sections and the first section does not contain a header (== header ==) it cannot be edited separately but you have to edit the complete article to change the section. This is especially bad if the page is very large where the complete page has to be loaded and saved back to the database.
1 Answer
In the Wikipedia Preferences page, go to the tab Gadgets subtab. Unde "Appearance`, check the box "Add an [edit] link for the lead section of a page".
