What version are you running?
2.5.3 alpha 0 (dev)  (https://reviews.reviewboard.org)
What's the URL of the page containing the problem?
Any review request
What steps will reproduce the problem?

Select some modified file with collapsed lines at the bottom of the diff and expand those collapsed lines.
Add a multi-line commend that would extend into the previously collapsed area.
Now re-collapse those lines.


What is the expected output? What do you see instead?
The green comment indicator bar on te left hand side now visually extends past the file where the comment exists and into other subsequent file(s).
Furthermore, refreshing the diff page turns the multi-line comment into a single line comment.
What operating system are you using? What browser?
Windows 7, Firefox 46.0.1
Please provide any additional information below.
See attached animated GIF for a clearer illustration of the problem.