The latest p7zip ebuild, and maybe the versions before, do no longer install the service menu entries for dolphin:5. The problem here is, that with USE="kde" the bin/7zG exe is built and installed, but the .desktop files are installed in /usr/share/kde4/services/ServiceMenus while dolphin:5 looks in /usr/share/kservices5/ServiceMenus Everything triggered by USE="kde" is still needed, but a way to tell the ebuild to install the service files for kservices5 instead of kde4 might be a good addition. Another USE flag maybe? (In the meantime, a work-around is to: 1) mkdir /usr/local/share/kservices5/ServiceMenus 2) cd /usr/local/share/kservices5/ServiceMenus 3) for x in $(sudo ls /usr/share/kde4/services/ServiceMenus/p7*.desktop) ; \ do sudo ln -s $x ; done Dolphin:5 looks there, too.)
mind testing this p7zip-15.09-r1
The ebuild installs in /usr/local/share/kservices5/ServiceMenus but it should be in /usr/share/kservices5/ServiceMenus
k, thought that was odd (the woraround mentions /usr/local) fixed in r2