Marking unconfirmed, I've tried with a edgy CD and on my feisty desktop and I don't get the bug. Downloading the 4 tarball you attached to the bug on the desktop and dnd them to the theme manager doesn't break the previews, the "?" are displayed for like one second and then the preview are displayed again correctly
** Changed in: control-center (Ubuntu) Status: Needs Info => Unconfirmed -- Theme previews go away after installing new widget themes https://launchpad.net/bugs/86282 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs