What version are you running? 2.0 RC3 What steps will reproduce the problem? 1. In an existing review request, click Update -> Upload Diff 2. Click Upload (with no other changes). What is the expected output? What do you see instead? There should be some sort of error saying that no diffs were selected. Instead, the "Loading..." spinner appears and nothing more happens. What operating system are you using? What browser? Windows 8.1 with Firefox 29.