After inserting a HR element, pressing return key creates a copy of this HR element in the document
1. With r17089, login to your writely (Google Docs and Spreadsheets) site
2. Click create a new document
3. Click in the Insert Tab. Click Separator - Horizontal Rule
4. After HR is inserted into the document, press the return key.
5. Notice a copy of the HR now appears in the document
No extra HR element should be inserted into the document after I press the return key but does.
This works fine in FF 184.108.40.206.
This issue is filed as <rdar://problem/4787966>