Created attachment 532545 [details]
Before and after
In bug 560755, the border for the location bar and search box was changed to ThreeDDarkShadow because the previous setting, a partially transparent black border, did not show up on a black background.
The downside of using ThreeDDarkShadow is that in most classic color schemes, it produces a completely black border, which is very jarring and inconsistent with the rest of the style of that upper region of the browser: no other border is nearly that dark, and it really stands out like a sore thumbs (especially when it is juxtaposed with the borders of the adjacent toolbar buttons).
As a compromise, I think we should use ThreeDShadow instead. Its color more closely matches that of the original partially transparent black, and it is still visible in a black high-contrast scheme. It doesn't stand out as much in HC, but none of the other borders do either (e.g., look at the border of tabs in black high-contrast), and most importantly, it still remains visible.
Attached is a screenshot showing the before-and-after of this proposed change:
* Normal classic: Note how incongruous the black border looks when juxtaposed with the nearby toolbar button borders and tab borders.
* High-contrast classic: The border is still visible, and although it does not stand out as much as before, none of the other borders in that region of the interface--tabs, buttons, etc.--do either.
* Themed: Just a sanity check to show that this is indeed a classic-only change.
Created attachment 532546 [details]
example showing that a gray-on-black text box is not unprecedented
This is just to show that there are already other prominent bits of text-input UI that use a gray border in a black high-contrast scheme...
Created attachment 532547 [details] [diff] [review]
(In reply to comment #0)
> It doesn't stand out as much
> in HC, but none of the other borders do either (e.g., look at the border of
> tabs in black high-contrast)
(In reply to comment #1)
> Created attachment 532546 [details]
> example showing that a gray-on-black text box is not unprecedented
> This is just to show that there are already other prominent bits of
> text-input UI that use a gray border in a black high-contrast scheme...
The theme doesn't really adjust to the OS theme at all there. Obviously not great examples -- we want to do better than that if we can.
Mozilla/5.0 (Windows NT 5.1; rv:6.0a1) Gecko/20110519 Firefox/6.0a1
Verified the change with the help of before/after image.