Sorry for my obsession with transparency - but I bumped into a trick - which many of you probably already know, but I did not know and no-one told me, so I am sharing it here, just in case there is someone like me that might benefit from it . 

If you recall, I have mentioned how Wayland handles GTK transparency better than X11. Well , I found a trick that can be used on X11 to make the same thing happen. In the above screenshot - I am in MX Linux / Xfce on Compiz  - I have my gtk.css set up for transparent menu-bar and toolbar ( among other things ) - The top window shows a Geany window when the application is invoked normally. You can see that the toolbar and menu-bar are pitch-black, even though gtk.css has them as transparent. However , if you call Geany with the environment variable GTK\_CSD=1  (bottom window) - voila - the menu-bar and toolbar are transparent .  

This trick works with almost any application that will otherwise not obey the transparency in gtk.css . I have tried it with old applications like SpaceFm - and it still works . 

There is a catch though - You will notice that I have lost my Emerald decoration from the bottom window, since GTK is now drawing the decoration; challenges with resizing come with that. Also I have not been able to make the panel calendar go transparent even with this hack. So I still need to leverage Compiz's 'fake' transparency for that one.

Transparency trick