What's the URL of the page containing the problem?

Any review page.

What steps will reproduce the problem?
1. Navigate to an open review request that you own.
2. Attempt to mark the review as submitted at a time when review board is
being slow.

What is the expected output? What do you see instead?

It'd be nice to see some sort of visual feedback that reviewboard is
processing the request. Instead, reviewboard just sits there until the
request completes.

What operating system are you using? What browser?

Windows 2008, 64-bit, firefox 3.0.7.