Hi Cyn, I don't know why that dialog isn't appearing. Does the page get grayed like it should appear, or is the button completely non-responsive? Could you check the About Policies page -- type or paste '''about:policies''' in the address bar and press Enter to load it. Normally, the Active panel on this page says "The Enterprise Policies service is inactive." Does yours list any policies that override normal Firefox behavior related to preferences or proxy settings? By the way, the internal address of that dialog is chrome://browser/content/preferences/dialogs/connection.xhtml so you could open a new tab and paste that into the address bar and press Enter to load it. For me, the window shrinks to fit the dialog, which is annoying, but I can maximize it again after using the dialog. Whether it works completely the same out of context as it does on the Settings page, I don't know. I haven't checked what happens when I use it.