SUMMARY The 'Molecular Editor' option is permanently greyed out but dependencies all seem to be installed. I have reviewed references elsewhere that suggest libeigen2-dev is required. However this cannot be installed using sudo apt-get install libeigen2-dev since this has been replaced by libeigen3-dev STEPS TO REPRODUCE 1. Installed Kalzium using 'Discover' software centre (up to date) 2. Kalzium didn't show 'Molecular Editor' button 3. Checked dependencies & made sure that OCaml, LibFacile, OpenBabel2, avogadro and chemical-mime-data are installed. libeigen2-dev not found. 4. Installed libeigen3-dev OBSERVED RESULT - Still not working EXPECTED RESULT - Expected to see button appear and function when clicked. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION