it seems that backward compatibility is broken with all
panels and windows borders.
they render incorrectly more specifically with solid rounded
1, border color is not rendered.
2, and when skinning titleBackgroundSkin the rounded corners
After a closer look it (and also at the flex3 backward
compatibility issues, that I had missed) it appear the Panel solid
borders are drawn beneath the panel's background.
so they are hidden by the background color and the only way
to get them visible is by lowering the background alpha property.
sounds like a bug to me.
This is indeed a bug. We have changed how the Panel skin
works in Flex 3 and it looks like this was introduced. If it isn't
already filed in our bugbase, I will file it. In the future, bugs
can be filed at: