From about 4.8 KDE I was black menu bar , older was transparency.
I fix this with tutorial:

1. Quit the application you have a problem with. If it's the desktop in KDE4, execute kquitapp plasma-desktop in a terminal or KRunner.
2. Open your filemanager and enter the URL above (~/.kde4/share/config).
3. It's often smarter to rename or move the files instead of deleting them. In this example, move all files starting with plasma-desktop in the directory to another place (to keep them as backup).
4. Start the application again (run plasma-deskop). The application should start with its default configuration now.

viewtopic.php?f=14&t=38828
http://www.pclinuxos.com/forum/index.ph ... 002.0.html

Maybe not all worked properly, ( sometimes I was bug with plasma desktop shell and maybe with VSync )
but I was my transparent menu bar.

I have problem in KDE 4.9.2-1
I click something example "show fps" in Desktop Setting -> Workspace Appearance and Behavior -> Desktop Effects -> All efects
I restart computer and I was black screen in Desktop and in window, only I saw graphic fps and menu bar.
I rename /.kde4/share/config , I have new menu bar but I have black screen too.
I rename also ~/.config , ~/.local , ~/.kde4 , now example dolphin window is not black
I have only this in 1 acount user, I can't find this file, I will try rename tmp file.

Edit:
Desktop-wallpaper problem solved.
Now I don't have black windows so I click Desktop Setting -> Workspace Appearance and Behavior -> Desktop Effects -> All efects
unticked all and this not working
in tab "General" I'm unticked "enable desktop effects at startup" and this working , wallpaper back.
( I think before I click on it )

In Desktop Setting is bug , The letter "D" does not fit -is too far to the left in "Desktop effects can be toggled anytime using this shortcut"


I have black menu bar in "Glassified" and grey in "Air fo netbooks" Desktop theme,
but how can I run transparent menu bar ?

Edit:
I remembered something, for me before transparent menu bar worked with compiz and "enable desktop effects" somewhere in the system.
So transparency working only with option "enable desktop effects at startup" ?
If YES so I need config mesa drive (because I have new installed system) and enable "enable desktop effects"
I will try, if someone has another idea, please write.

8.01.2013 Edit:
Now I have transparent menu bar, but I was scared.
I config mesa dri, "enable desktop effects at startup", off all effects plugins ,
reboot computer, and working !
I use something screen saver , maybe something else( I changed my resolution in control center )
, reboot, and only like terminal with login, in save mode too.
mv .kde4 .kde4-old , not working, after startx workiing , transparent menu bar also working.

9.01.2013
I have problem !!!
For starts KDE I need write startx every time, I don;t have "close system" , but only "logout", from KMix only PCM working , and don't have slider.
And sometimes I have strange momentary rainbow colors
How can I fix this?
Whit disable " "enable desktop effects ..." is this same.
Can I paste kdm.log here ?

10.01.2012 Edit:
Now I have in Kmix in PCM slider , but in Sorround disappeared.
New KDE4 is stable with normal mesa driver ?

Edit:
I have "Shut_down" KDE working, but with Kmix I have still problem. In Kmix I don't have "Sorround" slider.
KDE not worked before because something was wrong.
I wrong edit etc/modprobe.preload ( When I configure driver mesa ), but after reboot KDE was worked , maybe when I active "enable desktop effects" and reboot, something was crashed. I don't know.

Ok I trying "enable desktop effects at startup"
Error:
"18 desktop effects could not be loaded"
" For technical reasons it is not possible to determine all posible error causes,
Destktop effect system not running . "

In next bookmark I changed for: " compositing type: XRender and I have
Error:
"2 desktop effects could not be loaded."
"For technical reasons it is not possible to determine all posible error causes.
* Blur effect requires OpenGL.
* Startup Feedback effect requires OpenGL. "
This is OpenGL come from plugin new mesa driver? Or from package OpenGL?

11.01.2013 Edit:
No one knows?
Ok. So I believe XRender and OpenGL come from mesa driver and not all work, because OpenGL plugin working only with new graphics cards

October 8, 2012
Mesa 9.0 is released. This is the first version of Mesa to support OpenGL 3.1 and GLSL 1.40 (with the i965 driver).

( example: ati radeon with "HD" but not all , http://www.mesa3d.org/relnotes-9.0.html ).
I believe too, KDE use this plugin, so before when I used KDE and I was problem with VSyns, something in my KDE not working properly, this may
"desktop effects" plugin, but I don't know which ( rainbow colors problem). And when I was problem with VSyns fonts, this may problem with this
"desktop effects" plugin or this used to much memory in my graphics card, That would explain why the problem occurs only at higher load.
Graphic card developer who was doing it probably has a lot better and this problem not exist.
But I don't know. I don't know how debug this.

Ok I have transparent menu bar , I have 3D , KDE not too fast, animations are slow, menu working faster, but working , so I will close some animations, maybe this help.
I don't see bug with window, only in Kmix, So I write new topic, this topic may close.