I think it's not a bug in light-themes. I think the ubuntu software center is using a background-color, overriding gtk theme ones, thus it colors the progressbar. With Adwaita the problem is not noticeable because Adwaita is using a background-image, which in Gtk+ rendering has higher priority over background color.
** Changed in: light-themes (Ubuntu) Status: Confirmed => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1052936 Title: Progress bar in "Progress" section has a hole in it To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/light-themes/+bug/1052936/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs