That happens because the default order of the buttons in Lucid currently is maximize, minimize, close, and therefore the maximize button is round on the left side, the close button is round on the right side, end every oder border is straight. As far as I can see from the screenshot, you have changed the order of the buttons to minimize, maximize, close, that is why the rectangle can be seen around the minimize button, because if it would be in its default position it would blend with the other buttons sides.
-- window button minimize is in a square https://bugs.launchpad.net/bugs/535560 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
