Comment 4 for bug 1777518

The gtk3 VS gtk2 thing is a red herring. When run with --backtrace, the logs show that libreoffice crashes while trying to instantiate a JVM (which it probably doesn't do with the gtk2 plugin). This is a known issue, see bug #1699772. So another way of working around the issue would be to uninstall libreoffice-java-common. Or to simply run the following command in a terminal:

    sed -i '/enabled/c\<enabled xsi:nil="false">false<\/enabled>' ~/.config/libreoffice/4/user/config/javasettings_Linux_*.xml

Some functions of libreoffice won't work without Java (the most visible probably being libreoffice base), but most of the office suite should work just fine.