MATE does not use nautilus. It uses Caja.

Hello Dan.

Even if caja is the default file manager in mate, using nautilus or other file managers with mate is still a valid combination and should work correctly unless it's explicitly stated as unsupported. AFAIK caja is just a fork of nautilus from gnome2. It seems mate has a similar problem with configuring gtk3 themes like other gtk based desktops (xfce, lxde) had in the past and that needs to be fixed. If you believe the problem lies in a different component, then feel free to change it, but do not close this report, please. It has no sense to duplicate reports for each component where we're not sure what the root cause is.

Thank you.

Regards,
Jaromir.

This is definitely a theme error with the gtk-3 part of mate clearlooks.
But it's not a task for mate upstream to write a nautilus-wigdet.css for their theme.
I suggest to use the zukwito theme which is in fedora repos, has the best gtk2/3 support imo and it's optimised for gtk-3-3.6.
Another solution is clearlooks phenix.
http://www.jpfleury.net/en/software/clearlooks-phenix.php
If you like dark.
http://gnome-look.org/content/show.php/?content=153866
Or in general a gtk-2/3 theme.

Note:
gtk-2/3 support is on the mate roadmap for mate-1.6
http://wiki.mate-desktop.org/roadmap

Hello Wolfgang.

Thanks for the analysis and well descriptive answer. It's always questionable whose task this is. The most important thing is that users are innocent here. Unless there's any kind of "do not put a cat in the microwave" warning shown during the installation, then we need to consider this a distribution specific issue. If I understand correctly, the theme needs to be fixed or replaced with a similar one and removed. Right?

Thanks,
Jaromir.

Hello Jaromir.
normaly every gtk3 part of a theme needs to be updated if gtk-3 switch to a higher version. The gtk-2/3 themes from mate-themes are designed for gtk3-3.2 but they they working also well with gtk3-3.4.
The switch to gtk3-3.6 is very violently, in result some themes devs won't update anymore and obsolete some themes, which you have found on gnome-arts or deviantART.
Also themes for gtk3-3.6 doesn't work with gtk3-3.4.
I think this described the real prob.

In case of mate this means, that mate have to provide mate-themes in 3 different versions, because mate runs on different distros with different gtk3 versions. I think this is impossible to handle for mate upstream.

see my github account, here i have created a theme collection package for gtk2/3 called mate-themes-extra in 3 versions. Very hard and much work....
https://github.com/NiceandGently?tab=repositories

The second point is that some appps like nautilus in your case, needs special widget.css files (in gtk2 *.rc). Gedit and gnome-terminal is also a candidate for this.
And if someone do this for mate-themes, what is with nemo from cinnamon or any other app which needs a special widget.css?

And don't forget mate use gtk2, so gtk3 hasn't the highest piority.

honestly, mate needs a theme dev, hopefully we find someone for this big field in future.

cheers,
Wolfgang

Thanks for making it even more clear.

So ... to summarize that.

It seems to be a conflict of interests. We want to have the latest gtk3 and we also want to have mate. As I understood from your last comment, the mate upstream has not enough resources to keep up with the gtk3 innovations. That means we need to:

1.) help upstream
2.) hack it locally (temporary solution)
3.) close this as WONTFIX

Any other options?

I prefer the first one, but that would need somebody who has enough time to play with the themes.

GTK3 themes DO work with MATE.

Try Nimbus.

There is a plan to add GTK3 support for most themes in MATE 1.6

http://wiki.mate-desktop.org/roadmap