Rated 5 out of 5 stars

Best compact theme of all, many thanks to the developer.
There ist one little disturbing element after upgrading to 4.0.9: the black background at the top, especially when tabs are not on top.
I show you 2 screenshots so that you can see what I mean.
CC & CCO 4.0.9.1 with tabs on top: http://imageshack.us/photo/my-images/62/cctabsontop.jpg/ (it´s okay)
CC & CCO 4.0.9.1 with tabs NOT on top: http://imageshack.us/photo/my-images/27/cctabsnotontop.jpg/ (that´s ugly)

I have found a nice way to remove the black background here:http://userstyles.org/styles/33773/firefox-4-choose-your-color
This makes the CC theme complete unicoloured and you can either take one of the style offers or make your own colour by changing the values in the code that come after capital "RGB" or "RGBA"

Pease see my screenshot: http://imageshack.us/photo/my-images/849/ccmitchooseyourcolour.jpg/
(I changed the values after capital "RGB" or "RGBA" to 224, 223, 227 which is a little big darker than the original CC colour but brighter than the offered WinXP/WinClassic colour.)

It works perfectly with CC & CCO in FF 4 and FF 5.

If you could provide a similar option in CCO I would give you 10 stars. :-)
If not, please take at least my 5 and I will use CC with "choose your color" furthermore hoping both will work together well in future..

This review is for a previous version of the add-on (4.0.9.1). 

Black background because of Windows Aero Glass

The black background is caused by support I added for Windows Aero Glass. I could certainly work on adding an option to allow users to disable Aero Glass if they so desired. Over time, I will work on improving and refining Aero Glass support in Classic Compact based on user feedback.