*NOTE: Do not post confidential information in this bug report.*

What's the URL of the page containing the problem?
Any diff page for me.

What steps will reproduce the problem?
1. View the diff
2. Click the "Collapse changes" link
3. Click the "Collapse changes" link again

What is the expected output? What do you see instead?
Expect to see the changes in all the files collapsed/expanded, instead they
are always collapsed.

What operating system are you using? What browser?
ubuntu 8.04 and firefox 3.05

Please provide any additional information below.