I just upgraded my ubuntu from 15.10 to 16.04. On the old system I had libreoffice 126.96.36.199 on the newer system 188.8.131.52.
On the old version in libreoffice calc there is an option “Window → Split Window” (and also freeze Window). In the new version this option is gone. Why was this removed? Is this feature available in an other menu in the new version?