They are solid black - that's what make this issue stand out (for me). I'm talking about the very fine delineation line that separates the taskbar from the rest of the screen. If you take the above screeenshots and zoom in on them in any given image viewer, you'll see that the line in the Win7 taskbar does not gradate at all, while the DF one has the subtle highlighting.
Now in my defence (I don't normally suffer from a surfeit of perspicuity) one might well say "if you have to zoom in to see something, this can't be much of a bother" - but if you combine a black taskbar with a solid black wallpaper, from standard viewing distance this gradation towards the edges appears to be a colour-gradient flaw within the TFT's colour profile itself, which was the first thing I checked. Looking at it all day, and no matter how many times I remember it's intentional, I always think the backlight is causing a visual distortion, or some suspiciously cropped occurrence of stuck pixels is attacking me, if you know what I mean. It's just wrong. And if you rely upon your LCD for accuracy, it's important not to have doubts about its display integrity.
As (like I said) there is no gradating in the Win7 taskbar boundary (at least on mine), it's out of place on DF's (in my meagre opinion). True, there is the usual distortion surrounding the damnable "show desktop" button itself on the Win7 bar, but that's normal. The "line" is otherwise not affected.
At least contemplate a checkbox setting for "No silly frippery-frockery on the taskbar".
