Xfce Theme Manager: A Single GUI To Change Any Xfce Theme (With Previews)

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.