Comment 2 for bug 52524

Also, when you click on a site in the list, it would be helpful if the "Block" and "Allow" buttons could be used to change the status from whatever it is. (The button for the site's current status should be grayed out, I guess.)

Alternatively, clicking (or at least, double-clicking) on a site should copy its name to the "Address of web site": field, but that has problems because you might end up erasing something the user has typed in there.

There's an upstream bug about making the exceptions dialog more navigable (in particular, by making the list of sites less clumsy to browse and sort, and maybe add a few more informational columns); maybe this could be brought up there, too. (Perhaps they even have this particular bug already.)