Also, I can't get such clear outlines on the popup unless as you do unless I change the border_width is set to 3. The outmost black borderline is so blurry for me I can't hardly see it when border_width is set to 2. I guess this is because of some difference between different versions of cairo/pycairo. What disto do you use?
I've tested both with and without compositing, same result. Using Arch you probably have a newer version of cairo or pycairo than I do.
Could you run python and do import cairo cairo.version
It would help me quite a bit since it will tell me what kind of changes the looks of DockbarX is supposed to go through when Ubuntu 11.10 is released and gives me a chance to see if I need to change something in DockbarX code before that.
If I understand you correctly, that you use no composition, you should thinker a bit around <color1> as well. It's completely unused if you don't use composition since you use opaque gradients in the popup. But for people that use composition it's still used for the hover color of the window item, so you would perhaps want to set <color1> to something lightly blueish or whatever and perhaps change the name to something more describing than "Window list background"?