@chigy FYI

@widersky , thank you for your suggestion.
While it may not work on a colored background, we have a reason why it is the gray (and this very specific color of gray).

We introduced shadow to create contrast between the popup UI and the page. However shadow is something that turns off 1) if user choose to do so, 2) power capability does not allow it. So without the shadow, popup would blend in with the page when it is turned off if the page has the same or similar color.

We carefully examined the color combinations and came up with this gray to be 1) least outstanding, 2) provides the contrast when shadow is off, 3) it doesn't give too much of a line look when shadow is indeed applied.

In an ideal situation, we don't have to have the border to begin with and shadow can handle it, but we do not have such a system in place yet and this is the best design which still keeps our usability promise.

This is similar to a suggestion I made before about inner and outer borders for pop-over and flyout surfaces.

This ensures with or without a shadow, there is still some kind of border, which doesn't look quite as awkward.