Force LibreOffice 5.1.2.2 to use gtk2 instead of gtk3?

I have LibreOffice Version: 5.1.2.2, Build ID: 1:5.1.2-0ubuntu1 running on Lubuntu 16.04 LTS. It defaults to gtk3, but I want to know if I can switch it to gtk2 instead as hinted by comment #7 in https://bugs.launchpad.net/df-libreoffice/+bug/1527053. Is that possible? man libreoffice makes no mention of such a possibility.

Solution 1:

Uninstall libreoffice-gtk3 if you need the GTK2 version of LibreOffice.

Solution 2:

Start libreoffice with the environment variable SAL_USE_VCLPLUGIN set to gtk:

SAL_USE_VCLPLUGIN=gtk libreoffice

Depending on how you set up environment variables at boot, you can include the setting in the appropriate places.

Works for me under Arch Linux.

Note: Also supported: SAL_USE_VCLPLUGIN=kde4 for Qt, for example. See https://wiki.archlinux.org/index.php/LibreOffice#Theme.