System Settings -> Themes:
This is how "Window borders" section look like:

Here's what happens when I click on it:

Notice the small white strip. It doesn't show anything else. Just that. Rest of the sections of the window (icons, controls, mouse pointer, desktop...) work as expected, i.e. it shows actual things to choose from on click.
Cinnamon Version: 2.6.13
Try opening a terminal and running cinnamon-settings themes. See if any errors are generated when you attempt to open the menu.
No output on click. Here's the full log:
Python module
/usr/lib/cinnamon-settings/cinnamon-settings.py:184: Warning: The property GtkEntry:primary-icon-stock is deprecated and shouldn't be used anymore. It will be removed in a future version.
self.builder.add_from_file("/usr/lib/cinnamon-settings/cinnamon-settings.ui")
/usr/lib/cinnamon-settings/cinnamon-settings.py:184: Warning: The property GtkEntry:secondary-icon-stock is deprecated and shouldn't be used anymore. It will be removed in a future version.
self.builder.add_from_file("/usr/lib/cinnamon-settings/cinnamon-settings.ui")
/usr/lib/python2.7/site-packages/gi/overrides/__init__.py:313: 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)
Could not find bluetooth module; is the cinnamon-control-center package installed?
/usr/lib/cinnamon-settings/cinnamon-settings.py:429: Warning: The property GtkCellRendererPixbuf:follow-state is deprecated and shouldn't be used anymore. It will be removed in a future version.
pixbuf_renderer.set_property("follow-state", True)
Loading Themes module
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory apps/system-power-actions of theme breeze has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory apps/toolbar of theme breeze has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory categories/kickoff-menu-tabs of theme breeze has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory apps/system-power-actions of theme breeze-dark has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory apps/toolbar of theme breeze-dark has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory categories/kickoff-menu-tabs of theme breeze-dark has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory apps/system-power-actions of theme breeze has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory apps/toolbar of theme breeze has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme directory categories/kickoff-menu-tabs of theme breeze has no size field
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for breeze_cursors has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for Breeze_Snow has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for default has no name
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for default has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for KDE_Classic has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for Oxygen_Black has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for Oxygen_Blue has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for Oxygen_White has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for Oxygen_Yellow has no directories
(cinnamon-settings.py:27020): Gtk-WARNING **: Theme file for Oxygen_Zion has no directories
__init__ took 461.001 ms
Ok, mostly that just shows gtk not being a big fan of the kde stuff you have installed ;)
I have a sneaking suspicion what the issue is. I assume you're using a non Mint distro which has a much newer version of gtk. Try installing a couple of random metacity themes and see if it starts working properly. In newer versions of gtk the default adwaita theme no longer supplies a metacity theme of it's own. In those cases I think muffin is supplying you a default theme just so it has one. The directories the window borders setting is looking in for themes are probably empty and the reason you are getting the empty menu.
Seems to be correct assumption! However, I now can't switch to default (previous) theme through this menu.

And yeah, I'm using Arch Linux, so it's true that I'm using latest packages.
Not sure if this should be a new issue, as I'm having a related problem. But, on top of that I can't find "other settings" inside the themes window. There are no tabs. I'm also on arch, nothing crazy in the output when running it in terminal

@StrikeForceZero there is no other settings tab. All the settings are on that single page.
@JosephMcc how does one change the border thickness, button sizes... etc? Before it was in a tab "other settings" my mistake. looks like it was never an option. installing themes that support metacity did allow switching to other themes, but not back to the default.
The issue here on arch is that Cinnamon is not showing the GTK3 default theme of Adwaita, as it's not installed in the place Cinnamon expects /usr/share/themes/Adwaita/gtk-3.0/
On Arch, the only file that exists there is an empty gtk.css, but Cinnamon seemingly expects something more?
Any chance Cinnamon can support the 'default' of gtk3 given it's installed in a different location?
A workaround is simply to open dconfeditor
And change /org/cinnamon/desktop/wm/preferences to default
Any traction on this issue? Still exists with Cinnamon 3.2.
Any updates? The issues still exists on Cinnamon 3.2.8. I am using Arch Linux
So the arch users can't select Adwaita window borders?, is this correct?
Copying muffin-adwaita.txt to /usr/share/themes/Adwaita/metacity-1/ should make adwaita fallback theme show in cinnamon-settings themes (window borders).
http://pkgs.fedoraproject.org/cgit/rpms/muffin.git/tree/muffin-adwaita.txt
That theme was never really meant to be user selectable. It was added as a fallback in muffin in case a user removed all their other themes.
When Adwaita was moved to being a part of gtk they decided to ditch the metacity part of the theme for whatever reason. Probably in part because gnome shell didn't require it any more. That's when the fallback theme was added.
This wasn't a high priority since it's a non issue on properly packaged distros like Mint or the Fedora Cinnamon spin. They inlcude themes of their own instead of relying on muffins fallback. I really only marked it as a bug so I could dig it back up again at some point.
@ostrolucky, is this still an issue in Cinnamon 4.4?
I don't know, I don't use Cinnamon anymore.
@Vahan86 it is.
Most helpful comment
The issue here on arch is that Cinnamon is not showing the GTK3 default theme of Adwaita, as it's not installed in the place Cinnamon expects
/usr/share/themes/Adwaita/gtk-3.0/On Arch, the only file that exists there is an empty
gtk.css, but Cinnamon seemingly expects something more?Any chance Cinnamon can support the 'default' of gtk3 given it's installed in a different location?
A workaround is simply to open dconfeditor
And change
/org/cinnamon/desktop/wm/preferencesto default