awesome wm client.opacity and xterm

I've:

   client.connect_signal("focus", function(c)                                                                                                                             
        c.border_color = beautiful.border_focus                                                                                                                            
        c.opacity=1                                                                                                                                                        
    end)                                                                                                                                                                   
    client.connect_signal("unfocus", function(c)                                                                                                                                                                                                                            
        c.border_color = beautiful.border_normal                                                                                                                           
        c.opacity=0.9                                                                                                                                                      
   end)

To my lua.rc, but there is no opacity change neither in xterm or firefox. It's all the time set to 100% ( I've checked with dialog popup and signals were handled ). Do I need to do something more to have opaque clients available? I'm on Awesome 4.2 with Lua 5.3

Solution

You need to run a compositing manager like xcompmgr or compton for .opacity to have any effect.