I have kde-plasma/plasma-desktop-5.2.2 installed. File /usr/share/plasma/plasmoids/org.kde.plasma.kicker/contents/ui/FullRepresentation.qml has an import from the dev-qt/qtgraphicaleffects in line 22. Because of this, I was not able to launch KDE menu without aforementioned package.
Thanks, fixed in git. https://gitweb.gentoo.org/proj/kde.git/commit/?id=6e560fde9876e6c732068bcc234e0b696e5f6d07