Default Preferences not saved

[Willem Ferguson]

I have a curious case where the font type on the Defaults preferences 
tab is not saved. It comes up as Dejavu but I want Sans Serif. When I 
set it to Sans Serif and select APPLY, then the font is changed to 
Dejavu. When I close Subsurface and restart, the default font is back to 
Dejavu. In fact if I APPLY any settings, even on other preferences tabs, 
the font is changed to Dejavu. Could this be because of patch 5400759??

Actually I suspect this is not a coding problem, but a problem of the 
absence or locations of setup files.
Kind regards,
willem