{"action":"opened","issue":{"url":"https://api.github.com/repos/webcompat/web-bugs/issues/2767","repository_url":"https://api.github.com/repos/webcompat/web-bugs","labels_url":"https://api.github.com/repos/webcompat/web-bugs/issues/2767/labels{/name}","comments_url":"https://api.github.com/repos/webcompat/web-bugs/issues/2767/comments","events_url":"https://api.github.com/repos/webcompat/web-bugs/issues/2767/events","html_url":"https://github.com/webcompat/web-bugs/issues/2767","id":160782683,"number":2767,"title":"www.twitch.tv - see bug description","user":{"login":"mstange","id":961291,"avatar_url":"https://avatars.githubusercontent.com/u/961291?v=3","gravatar_id":"","url":"https://api.github.com/users/mstange","html_url":"https://github.com/mstange","followers_url":"https://api.github.com/users/mstange/followers","following_url":"https://api.github.com/users/mstange/following{/other_user}","gists_url":"https://api.github.com/users/mstange/gists{/gist_id}","starred_url":"https://api.github.com/users/mstange/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mstange/subscriptions","organizations_url":"https://api.github.com/users/mstange/orgs","repos_url":"https://api.github.com/users/mstange/repos","events_url":"https://api.github.com/users/mstange/events{/privacy}","received_events_url":"https://api.github.com/users/mstange/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-06-16T23:24:12Z","updated_at":"2016-06-16T23:24:12Z","closed_at":null,"body":"<!-- @browser: Firefox 50.0 -->\n<!-- @ua_header: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:50.0) Gecko/20100101 Firefox/50.0 -->\n\n**URL**: https://www.twitch.tv/rahmschnitzel\n**Browser / Version**: Firefox 50.0\n**Operating System**: Mac OS X 10.11\n**Problem type**: Something else - I'll add details below\n\n**Steps to Reproduce**\nHow common is the usage of ::-webkit-scrollbar, and how severe are the web compat problems in Firefox due to Firefox not supporting it?\r\n\r\nThis topic came up at the planning session of the mozilla layout team today. We'd like to know if implementing ::-webkit-scrollbar is a high priority issue for Firefox web compat.\r\n\r\nThere are three issues I'm concerned about here:\r\n1) users preferring other browsers because of bad-looking scrollbars\r\n2) web developers being unhappy because they can't have custom-looking scrollbars without clumsy workarounds\r\n3) actual issues caused by those workarounds.\r\n\r\nItem three is the major one. The issues I know about are:\r\n - Twitch has a custom overlay scrollbar and wants to hide the scrollbar provided by the browser. It does that using ::-webkit-scrollbar { width: 0; height: 0; }. With OS X overlay scrollbars, this creates two overlapping scrollbars in Firefox because the scrollbar provided by Firefox is not being hidden. You can see this middle scrollable pane on any twitch channel, e.g. https://www.twitch.tv/rahmschnitzel .\r\n - With async scrolling in Firefox (e10s-only), website-implemented scrollbars can lag behind. Native Firefox scrollbars track scrolling even if the main thread is busy. This can be seen on Facebook in the mini newsfeed in the top right corner, above that chat list. Facebook uses a custom scrollbar in that box, and scrolling rapidly up and down in e10s Firefox makes the scrollbar show up in unexpected places.\r\n - In general, there's more that can go wrong when websites implement their own scrollbars.\r\n\r\nI'm interested if you have any other information about compat problems caused by this, and whether you have usage stats on this feature.\n\n\n\n_From [webcompat.com](https://webcompat.com/) with ❤️_"}}
{"actor":{"display_login":"mstange"}}