Which GUI toolkit is used by LO?

I would like to know which GUI toolkit is actually used by LO?

It uses its own (vcl) that can hook up into GTK and QT (linux and quartz on mac) to draw native controls. Only thing that really is used natively is the filepickers (unless you check [x] use LibreOffice dialogs under Load/Save in Tools|Options → LibreOffice → General)
output device).

Visual Components Library is
responsible for the widgets
(windowing, buttons, controls, etc.)
operating system abstraction,
including basic rendering (e.g. the
output device).output device).


Could somebody please remind my how to select the GUI toolkit to start LibreOffice with? I remember there was some environment variable, defining which one could choose the toolkit to start LO with, but I just forgot the name of this variable.

Thanks in advance!

Got an answer here: Choose GUI toolkit for LO session