karog wrote:Neither of you stated which EdgeRouter you have. The image looks like an ERX given the interfaces shown.
I have an ERL running 1.9.0 and I usually use Chrome which works fine. So I just tried the GUI using Safari 9.1.2 on OS X 10.10.5 Yosemite and it also works fine. I cannot speak for El Cap.
I'm using an ER-X. Chrome works for the most part, however there was a pretty bad regression introduced in v1.9.0:
http://community.ubnt.com/t5/EdgeMAX/Regression-in-FW-1-9-0/m-p/1655510
So at this point, there isn't any browser that works properly to be able to configure interfaces at the bottom of the list.