"Same color for background-color and border-top-color" warning even with alpha transparency

Hello,

the CSS validator gives a warning when an element's background color is 
the same as its border color.
This makes sense for 100% opaque colors, however when there is alpha 
transparency, the border will be drawn on top of the background. This 
results in a different visible color.
Therefore, the warning should not be issued when at least one of the two 
colors has an alpha component different from 1 (100%).

Kind regards,
David Scherfgen