Created attachment 8928190 [details] Screenshot User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Firefox/52.0 SeaMonkey/2.49.1 Build ID: 20171016003553 Steps to reproduce: I've installed SeaMonkey on my Retina MacBook running macOS 10.13. Actual results: Everything inside the SeaMonkey window (UI, webview) is scaled twice from half the native resolution. Expected results: I expect SeaMonkey to be a normal app supporting Retina, so that macOS wouldn't have to scale it, like Firefox.
We know that is a problem. Could you set layout.css.devPixelsPerPx from -10.0 to 1.5 or 2 and see if this works better Icons might not look so good because we need to convert them to vector.
opps from -1.0 not -10.0