Option to merge changes not given under certain circumstances

If two users make simultaneous edits to the same page, the option to merge isn't always presented. Instead, one of the two pages will show a conflict with the entire other page and therefore not have the option to merge.

To reproduce:

1. User 1 opens page for editing in Confluence and make minor edits in one section
   time passes...
2. User 2 opens page for editing, sees message that User 1 is editing, then makes unrelated edits in another area of page
3. User 1 saves before the message about User 2 editing appears
4. User 2 attempts to save, and is then presented with a listing that appears that User 1 made many more changes than they actually did. No option is given to merge.