To build a AIR application with custom window(which has your own shape), try the fallowing:
In the <project_root>/src folder, open the XML file named “<your_project_name>-app.xml” and modify the two lines:
<!–<systemChrome>none</systemChrome>–>
to
<systemChrome>none</systemChrome>
and
<!–<transparent></transparent>–>
to
<transparent>true</transparent>
Then in your main page,
<mx:WindowedApplication xmlns:mx=”http://www.adobe.com/2006/mxml” layout=”absolute” showFlexChrome=”false”>
<mx:Script>
<![CDATA[
public function startMove(event:MouseEvent):void {
stage.nativeWindow.startMove();
}
]]>
</mx:Script>
<mx:Image id=”mainPanel” mouseDown=”startMove(event)” x=”10″ y=”10″ width=”300″ height=”200″
source=”myBg.gif /*path to a transparency image*/” scaleContent=”true” />