I'm still getting the issue here, except in my case the corners are white instead of black.
** Attachment added: "GNOME Calendar white corners in Ambiance under Unity" https://bugs.launchpad.net/unity/+bug/1516403/+attachment/4633176/+files/Screenshot%20from%202016-04-11%2016-52-14.png -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to gtk+3.0 in Ubuntu. https://bugs.launchpad.net/bugs/1516403 Title: Upper angles of window not curved Status in Unity: Confirmed Status in gtk+3.0 package in Ubuntu: Fix Released Status in unity package in Ubuntu: Fix Released Status in gtk+3.0 source package in Xenial: Fix Released Status in unity source package in Xenial: Fix Released Bug description: Hallo The upper angles aren't curved as all the other windows, see attached screenshot. Best regards ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: gedit 3.18.2-1ubuntu1 ProcVersionSignature: Ubuntu 4.2.0-19.23-generic 4.2.6 Uname: Linux 4.2.0-19-generic x86_64 ApportVersion: 2.19.2-0ubuntu6 Architecture: amd64 CurrentDesktop: Unity Date: Sun Nov 15 17:21:04 2015 EcryptfsInUse: Yes InstallationDate: Installed on 2015-10-11 (35 days ago) InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20151010) SourcePackage: gedit UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1516403/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp