Due new-style glib-2.28 url handlers for web and mail, desktop file needs to also add: x-scheme-handler/http;x-scheme-handler/https; to "MimeType=" to let it appear in gnome-default-applications-properties Thanks a lot Reproducible: Always
$ grep ^MimeType /usr/share/applications/opera-browser.desktop MimeType=text/html;text/xml;application/xhtml+xml;text/vnd.wap.wml;text/wml;application/x-mimearchive;application/mime;application/xml;application/rss+xml;application/rdf+xml;image/svg+xml;application/x-opera-uniteapplication;application/x-opera-extension;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp;x-scheme-handler/mailto; Looks like it has already been fixed in 11.10.