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.
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.