In a article when you click on the "Edit" link you edit just that section. So it adds the section name as a comment in the edit summary, for example as:
/* External links */
Then the user writes the edit summary after that. Example:
/* External links */ Removed a spam link.
This have two problems.
- The section comment can be removed or changed. This strips metadata.
- Breaks the browser's autocomplete feature.
The user would type "Fi" and the browser would present autocomplete suggestions based on previously entered edit summaries, such as "Fix typo", "Fix link", "Fix date", etc. But when you have "/* External links */" then the autocomplete don't find any history for that since it would have to be for every section name.
A solution would be enforce the the section in the comments and making it not possible to alter it.
Pseudocode
From:
<input type="text" name="summary" value="/* $section_name */ " />
To:
<span>$section_name</span> <input type="hidden" name="section" value="$section_name" /> <input type="text" name="summary" />