I use a desktop file to start libreoffice with a document to open. The desktop file is used from a quicklauncher in a bottom panel. What I often see since 16.12 (had no issue in 16.08) is the spinning animation in the taskbar when I start loffice, which keeps spinning although - loffice is already up and running - I explicitely have StartupNotify=false in the desktop file (why do I see the spinning at all?) Here is the .desktop file: [Desktop Entry] Comment[en_US]= Comment= Exec=xdg-open ~/Aufwand.xls GenericName[en_US]= GenericName= Icon=kspread MimeType= Name[en_US]=Aufwand Name=Aufwand Path= StartupNotify=false Terminal=false TerminalOptions= Type=Application X-DBUS-ServiceName= X-DBUS-StartupType= X-KDE-SubstituteUID=false X-KDE-Username=
Add a StartupWMClass to your .desktop file that matches the WM_CLASS of the eventual LibreOffice window.
(Note that this will probably work better with 5.10 / git, as we recently rewrote StartupWMClass handling somewhat.)