For T187614: Metadata (author, edit comment, navigation links etc) not shown in historic visual diff, the Visual Diff clones the header of the diff. While this works, there are some problems with this approach:
- It will clone any tr.diff-title, even if it is some user-generated content from the article shown below.
- This results in duplicated IDs, e.g. #mw-diff-otitle1, which is both invalid and could cause problems with any of these and similar scripts.
These issues aren't just hypothetic ones, I struggled with both while updating my script https://de.wikipedia.org/wiki/Benutzer:Schnark/js/diff.js, which adds a third diff mode. (Though due to T171437 this script already has a lot of hacks, so it didn't really matter to add even more.)
Other bug reports: