Just by chance, I took the GTK3 folder from the preinstalled Ambiance theme in my /usr/share/themes folder, and used it to replace the GTK3 folder in RAVEfinity's theme. This solved the problem with GTK3 applications not liking RAVEfinity's version of Ambiance, and now all apps look great!!! No ugly-looking GTK3 apps anymore!!
Let me know if it works for you.
You can see the screenshot. Thunar, Brasero and Totem all are correctly themed. And the XFCE panel looks great, too.
INSTALL: Extract the zip file into /usr/share/themes. You need to open pcmanfm or thunar with root privileges to do that. In the terminal, sudo pcmanfm (for LXDE) or sudo thunar (for XFCE). Then choose this theme from your appearance manager.
Enjoy!

Ratings & Comments
6 Comments
porque al lanzarlo como su (superusuario), el usuario root puede hacerse dueño de los archivos que vas a manipular, cambiándose los permisos. Cuando vayas a acceder a ellos como usuario normal tendrás problemas y es posible que te haga dar unas cuantas vueltas hasta que descubras el motivo. Y pensarás, "¿por qué se han cambiado los permisos si yo no he dado la orden? y le echarás la culpa al sistema, que difícilmente falla. Al ejecutar gksu, se crea un front-end que manipula el archivo sin permitir esa situación, porque hace una copia de .Xauthority (permisos de gráfica) a la carpeta /tmp, temporal. Cuando cierras la aplicación, se elimina y aquí no ha pasado nada. Con "sudo" no hay front-end ni copia a /tmp. Al acabar, el archivo permanece con root como dueño. Quizá mejor explicado: http://www.kubuntu-es.org/wiki/sistema/por-que-se-debe-usar-kdesu-o-kdesudo-ejecutar-aplicaciones-graficas-terminal-vez-usar-s. Saludos y procura escribir en inglés, para que lo entienda más gente. Because on having ran it as sudo (superuser do), the user root can become owner of the files that you are going to manipulate, changing the permissions. When you try to accede to this files as normal user later, you will have problems and it's possible that you waste your time stupidly until you discover the cause. And you will think, " why have permissions changed if I have not given the order? And you will think that the fault is from the system, which difficultly fails. On having executed gksu, there is created a front-end that works with the file without allowing this situation, because it does a copy of .Xauthority (permissions of X -graphics-) to the folder/tmp, the temporary directory. When you close the application, it is eliminated and nothing is happened at all. With "sudo" there is no front-end and not even copy to/tmp. On having finished, the file remains with root as owner. Greetings and here speak english, please. Is better to help others...
aaahh... ya entiendo. :) Uno nunca termina de aprender!
When you launch a graphic app in sudo mode, the formula is gksu xxxx (your file manager) not with sudo. Greetings!
Oh, gracias por el dato. Pero, ¿hay alguna razón en particular para eso? Cuando escribo sudo thunar en la terminal, thunar se abre con privilegios de root. La verdad es que no sé mucho de eso, así que si tú lo dices... bienvenido sea. :D Voy a ver qué pasa cuando uso gksu.
Looks very cool but the GTK3 contextmenus i.e, of NetworkManager are extremely hard to read. Would be nice if you could fix this too
Hello. As I said in the description, this is not my work. I just mixed two themes by chance and this is the result. I uploaded this only because this solved my problem with GTK3 apps, which were not themed when I used RAVEfinity's original LXDE-XFCE theme. Hopefully somebody can fix the problem you are mentioning.