1. Go to https://findit-for-me.appspot.com/waterfall/flake?redirect=1&key=ag9zfmZpbmRpdC1mb3ItbWVyrgELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJ4Y2hyb21pdW0ubGludXgvTGludXggVGVzdHMvNTk1NjYvYnJvd3Nlcl9zaWRlX25hdmlnYXRpb25fdW5pdF90ZXN0cy9RWEJ3UkdGMFlVMXBaM0poZEc5eVZHVnpkQzVHYVd4bFUzbHpkR1Z0VFdsbmNtRjBhVzl1DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw
2. Mouse over one of the dots on the graph to show the details popup
3. Try to click on one of the links in the details popup

When you move your mouse to click on the link, the popup goes away. As I was filing this bug, it occurred to me that it might stay if I clicked on the button, but that wasn't at all obvious.

It's probably worth having an easier to user UI.