The current DESCRIPTION of oxygen-gtk reads: "(yet another) Gtk port of KDE's oxygen widget style" I think this is a bit wrong. It's not "yet another Gtk port". This does the project injustice. It's pretty much the official Gtk port of Oxygen and in bugs.kde.org it's actually a component of Oxygen (named "gtk-engine"). It's in KDE Playground. I'd even go as far as suggesting a "gtk" USE flag for kde-base/kstyles that pulls-in oxygen-gtk :-) Anyway, the point is that the current description in the ebuild does not reflect the above. Maybe something like "Port of the default KDE widget theme (Oxygen), to Gtk". At least the "yet another" part should go, since contrary to the other "yet anothers", this one actually works (Gtk apps really look like Qt/KDE apps and KDE settings are respected.)
Fixed in latest version (1.0.1), thanks for reporting.