Hi @ferdinand ,
Thanks a lot, that's exactly what I was looking for !
flags: c4d.BaseContainer = c4d.BaseContainer()
flags[c4d.FILENAME_DIRECTORY] = True
# Add a CUSTOMGUI_FILENAME with our flags settings.
self.AddCustomGui(id=MyDialog.ID_FILENAME,
pluginid=c4d.CUSTOMGUI_FILENAME,
name="Path",
flags=c4d.BFH_SCALEFIT,
minw=0, minh=0,
customdata=flags)