Xinerama = 1 loses theme [closed]
Solution 1:
It's a workaround for themes not applying in Cinammon with Xubuntu, but you could try: setting a GTK3 theme as default in XFCE configs, and, login again in Cinnamon from here.
Different problem, but it might work to get the theme to apply.
I don't know what DE you're using, but it's definitely not Unity.