When using oxygen-gtk theme for gtk-apps with gtk+-3.14.9 (seems that any version >= 3.13.7) content of radio buttons, checkboxes and lists is not displayed when they are checked. More details: https://bugs.mageia.org/show_bug.cgi?id=13954 Upstream: https://bugs.kde.org/show_bug.cgi?id=338538
When I downgrade to gtk+-3.12.2, then everything is ok.
Sorry, after re-emergin oxygen-gtk the issue has gone away.