Focus in all cases

Have you also noticed that Flex draws a focus border around its components when you give them focus using the keyboard (by using the tab button)?

Great but why is the focus border not drawn when using the mouse to give a component the focus?

The solution is simple: extend the existing components and force the border drawing yourself:

<mx:CheckBox
      xmlns:mx="http://www.adobe.com/2006/mxml"
      focusIn="onFocusIn()">
<mx:Script>
//
// Support to draw the focus border on focusIn
//
private function onFocusIn(): void
{
      this.drawFocus(true);
}
</mx:Script>
</mx:CheckBox>