What is mx_internal?

From: http://cookbooks.adobe.com/index.cfm?event=showdetails&postId=12212

Problem

Looking at the Flex framework code, several properties and functions are prefixed with mx_internal. What is this?

Solution

mx_internal is a namespace used by the Flex framework to partition out functions and properties that may change in future releases of the Flex SDK.

Detailed explanation

mx_internal is a namespace used by the Flex framework to partition out functions and properties that may change in future releases of the Flex SDK.

You can access properties and functions in this namespace as shown below:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" creationComplete="myFunction()">

    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.controls.Text;

            import mx.core.mx_internal;
            use namespace mx_internal;

            private function myFunction():void
            {
                Alert.show(String(txt.styleSheet));
            }       
        ]]>
    </mx:Script>
    <mx:Text id="txt"/>
</mx:Application>

Note: Be aware that properties or functions defined may change in future versions of SDK.