Turns out this is a bug in light-themes, not GTK+. Adwaita does the right thing. See https://bugzilla.gnome.org/show_bug.cgi?id=670018 for a test program and reproduction steps.
** Also affects: light-themes (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to deja-dup in Ubuntu. https://bugs.launchpad.net/bugs/929128 Title: deja-dup backup window is white on lightgrey, white text on white background in details Status in Déjà Dup Backup Tool: Fix Released Status in GTK+ GUI Toolkit: New Status in “deja-dup” package in Ubuntu: Fix Released Status in “light-themes” package in Ubuntu: New Status in “deja-dup” package in Debian: New Status in “deja-dup” package in Fedora: Unknown Bug description: Deja-dup "Backup now" is white on light grey. The details widget draws white text on white background. Screenshot is attached. gtk3-engines-unico: Installed: 1.0.1-0ubuntu2 Candidate: 1.0.1-0ubuntu2 ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: light-themes 0.1.8.28.1 ProcVersionSignature: Ubuntu 3.2.0-14.23-generic-pae 3.2.3 Uname: Linux 3.2.0-14-generic-pae i686 ApportVersion: 1.91-0ubuntu1 Architecture: i386 Date: Wed Feb 8 23:27:53 2012 InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20120119) PackageArchitecture: all SourcePackage: light-themes UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/deja-dup/+bug/929128/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp