Q:

Add padding to a titlewindow in Flex 4 (ideally using skins)?

By default TitleWindows seem to have no padding. I tried the properties "left", "right" etc and it doesn't work. Actually I'd like to have a default for my whole app, so I tried creating a skin but no matter where in the skin I add 'left="50"' it just doesn't create padding on the left. You'd think that you should add it to the element with id="contentGroup", as described on this Adobe Skinning help page, but that does not work.
Surely this is something almost everyone wants to do?

A:

The contentGroup in the default TitleWindowSkin is inside a VerticalLayout which does not respect top/left/right/bottom constraints.
You could do this by duplicating the default TitleWindowSkin and wrapping the contentGroup with a Group with width/height of 100%:
...
<s:Group width="100%" height="100%">
    <!--- @copy spark.components.SkinnableContainer#contentGroup -->
    <s:Group id="contentGroup" top="10" left="10" right="10" bottom="10" minWidth="0" minHeight="0" />
</s:Group>
...

