Can't get white background

Question

I want every container to have a white background. No matter
what I do the child panel gets a gray background. I've tried every
combination of backgroundColor, backgroundGradient,
backgroundAlpha, etc. that I can think of.
Here's one try, using styleName="plain", which is supposed to
create a white background. The application outside the panel is
white, but the panel is gray.
<?xml version="1.0"?>
<mx:Application xmlns:mx="
http://www.adobe.com/2006/mxml"
styleName="plain"
dropShadowEnabled="false">
<mx:Panel title="Panel" dropShadowEnabled="false"
backgroundColor="#FFFFFF">
<mx:HBox>
<mx:Button label="Button" />
</mx:HBox>
</mx:Panel>
</mx:Application>
I'm pretty sure I didn't have this problem with beta 3.
Please, any method that gets a pure white background would be
appreciated.

Answer 1

With your sample, I tried adding
width="50%" height="50%"
to the <mx:Panel> tag, and then I saw that the main
content area of the panel
did in fact have a pure-white background; but the title area
and border area
of the panel are gray. With your original sample, the entire
content area is
filled with the button, and the button itself has a gray
background, so it
makes it appear as if the backgroundColor attribute had no
effect, when in
fact it did have an effect.
If you also want to set the title & border area of the
Panel to white, I found
that I was able to do that with
borderColor="#ffffff"
And there is also borderAlpha, which defaults to 0.4.
- Mike