LibreOffice 5.4 not using GTK3

[StuntHacks]

I am on Ubuntu 16.04 and using LibreOffice 5.4.3.2.

The program doesn’t use GTK3, no matter what I try. I tried setting the SAL_USE_VCLPLUGIN-variable to gtk3 and I even reinstalled the whole package. However, nothing works.

Does anybody know how to solve this?

[RGB-es]

Not sure about ubuntu, but on openSUSE GTK3 integration is installed as a separate package. Check on your package manager for something like libreoffice-gtk3 and install it.