Gtk-window-decorator themes in XFCE/Compiz broken after recent upgrade

Question

I allowed my arch linux upgrades to slide for a while - probably nearly a month - and just did a system upgrade and reboot today. After rebooting, I am stuck with GTK's default Adwaita window borders, which use a lot of real estate, and GTK3 apps like nautilus have a solid black border around the windows.
I have tried changing the theme with theme-switch2, I have rebooted a couple of times, replaced the window manager with xfwm4 and then gone back to gtk-window-decorator, all with no change. Other aspect of the theme - fonts and colors - work fine, but the window decorator theme just won't change.
The following commands have no effect:
gsettings set org.gnome.desktop.wm.preferences theme Numix
gsettings set org.gnome.desktop.interface gtk-theme Numix
Here is an example of the black box around nautilus.
Possibly unrelated, but when I start gnome-tweak-tool, which allows me to change the theme, I get the following message:
WARNING : Shell not installed or running
WARNING : Error detecting shell
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/gtweak/tweaks/tweak_group_shell_extensions.py", line 274, in __init__
raise Exception("Shell not running or DBus service not available")
Exception: Shell not running or DBus service not available
/usr/lib/python2.7/site-packages/gi/overrides/__init__.py:306: Warning: The property GSettings:schema is deprecated and shouldn't be used anymore. It will be removed in a future version.
return super_init_func(self, **new_kwargs)
INFO : GSettings missing key org.gnome.nautilus.desktop (key computer-icon-visible)
WARNING : Error loading desktopfile: /home/dacre/.config/autostart/tracker-miner-apps.desktop
WARNING : Error loading desktopfile: /home/dacre/.config/autostart/nm-applet.desktop
WARNING : Error loading desktopfile: /home/dacre/.config/autostart/blueman.desktop
WARNING : Error loading desktopfile: /home/dacre/.config/autostart/xfce4-clipman-plugin-autostart.desktop
WARNING : Error loading desktopfile: /home/dacre/.config/autostart/xfce4-notes-autostart.desktop
WARNING : Error loading desktopfile: /home/dacre/.config/autostart/Growl For Linux.desktop
WARNING : Shell not running
None
INFO : GSetting missing org.gnome.shell.calendar
INFO : GSettings missing key org.gnome.settings-daemon.plugins.power (key lid-close-battery-action)
INFO : GSettings missing key org.gnome.settings-daemon.plugins.power (key lid-close-ac-action)
INFO : GSettings missing key org.gnome.settings-daemon.plugins.power (key lid-close-suspend-with-external-monitor)
Contents of `.config/gtk-2.0/settings.ini`:
[Settings]
gtk-theme-name = "Numix"
Contents of `.config/gtk-3.0/settings.ini`:
[Settings]
gtk-application-prefer-dark-theme=0
gtk-theme-name = Numix
gtk-fallback-icon-theme = gnome
gtk-icon-theme-name = gnome
gtk-font-name = Terminus 12
Contents of `.gtkrc-2.0`:
# -- THEME AUTO-WRITTEN BY gtk-theme-switch2 DO NOT EDIT
include "/usr/share/themes/Numix/gtk-2.0/gtkrc"
include "/home/dacre/.gtkrc-2.0.mine"
# -- THEME AUTO-WRITTEN BY gtk-theme-switch2 DO NOT EDIT
I am no expert in themes, so I am completely stumped by this whole problem. Any ideas anyone?

Answer 1

MikeDacre, there is a known issue whereby a change in GTK 3.16 means that Compiz isn't getting the frame extents for CSD windows. It's being discussed in the following Compiz branch: https://code.launchpad.net/~3v1n0/compi … rge/250015
I'm not entirely sure whether this is the relevant issue for you; my CSD windows don't have black borders but they do have a thin light grey border all the way around which negates the rounding of the top corners. You could try building Compiz from the branch I mentioned but just to warn you I've already tried and it didn't do anything for me. The bottom line is, the Compiz team need to fix Compiz for CSD and until they do, expect there to be problems.