Xfce uses multiple settings GUIs for setting the window border, controls, icons, mouse cursor theme and so on and it doesn't include any thumbnails. However, if you customize your Xfce desktop frequently, you can use a tool called Xfce Theme Manager which allows you to change the themes from a single GUI and it also includes thumbnails so you can see how the theme looks like before applying it.
Xfce Theme Manager allows settings the following:
- complete Xfce theme (window border, controls)
- window borders only
- controls only
- icon theme
- cursor theme
- change the wallpaper
Also, under "Advanced" (screenshot above), you can adjust various settings like backdrop brightness and saturation, window button layout, window title position, change the fonts and the cursor size.
Other features included in Xfce Theme Manager:
- customizable theme preview size: you can choose between huge, large, medium and small previews;
- save the current theme (in case you use the window border from one theme and the controls from another theme for instance) which includes the wallpaper, font and so on;
- install themes using drag'n'drop (the themes must be tar.gz archives);
- reset the theme.
I did find one annoyance with Xfce Theme Manager though: when installing new themes, you must click the "Rebuild DB" (rebuild the themes database) under "Advanced" or else the newly installed themes won't show up or at least not immediately.
Here are a few more Xfce Theme Manager screenshots:
Install Xfce Theme Manager in Xubuntu
Xubuntu users can install Xfce Theme Manager from a PPA. The packages in the PPA below require Xfce 4.10, which is available by default in Xubuntu 12.10 and 13.04, but it's not available in Xubuntu 12.04 so for it, you'll also need to add the Xfce 4.10 Xubuntu 12.04 PPA! Alternatively, you can also build it from source (download link at the bottom of the post).
That said, let's add the PPA and install Xfce Theme Manager in Xubuntu:
sudo add-apt-repository ppa:rebuntu16/other-stuff sudo apt-get update sudo apt-get install xfce-theme-manager
Once installed, the application should show up in the Xfce Settings Manager.
If you're not using Xubuntu, you can download Xfce Theme Manager from xfce-look.org.