Ok. I managed to fix it following the instructions from here: https://wiki.archlinux.org/index.php/Qt#Configuration_of_Qt5_apps_under_environments_other_than_KDE
and installing qt5ct from here: http://ppa.launchpad.net/nilarimogard/webupd8/ubuntu/pool/main/q/qt5ct/. Regards. Ariel
