How does derived class access mx_internal namespace ?

Question

Hi,
I've been struggling with the PopUpButton for a day now.. Just trying to move the popup location. Since I can't get moving the PopUpButton into my directory and have it find the icons, I'm attempting to subclass PopUpButton.
Some of the methods in PopUpButton  are defined as mx_internal. I cannot seem to access the methods during runtime. I get an error:
Main Thread (Suspended: TypeError: Error #1006: value is not a function.)
ViewControl/clickHandler
I can compile the code, prefixing the specific function with "mx_internal."
Here is the code:
package {
import flash.events.Event;
import flash.events.FocusEvent;
import flash.events.KeyboardEvent;
import flash.events.MouseEvent;
import mx.core.mx_internal;
import mx.controls.PopUpButton;
use namespace mx_internal;
public class ViewControl extends PopUpButton
  public function ViewControl(state:String = ViewSelectorState.TILE, value:Number=0):void
   super();
   /* Add the popup */
   _renderer = new ViewSelectorRenderer();
   super.popUp = _renderer;
  /* override the click */
    override protected function clickHandler(event:MouseEvent):void
     if (overArrowButton(event))
        if (mx_internal.isShowingPopUp())
         mx_internal.closeWithEvent(event);
        else
         mx_internal.openWithEvent(event);
        event.stopImmediatePropagation();
     else
        super.clickHandler(event);
        if (openAlways)
         if (mx_internal.isShowingPopUp())
            mx_internal.closeWithEvent(event);
         else
            mx_internal.openWithEvent(event);      

Answer 1

I haven't yet had the need to use a mx_internal, however there are 2 differences that may be a problem which I saw between your code and the link below:
Flex 3 Looping over itemRenderers in a List
Those differences are:
-import mx.core.mx_internal; //this import statement should appear be last.  So, for some reason I assume the author is saying to have that listed last, out of all of your imports.
-use namespace mx_internal; This line is nested between the class brackets.  Yours is nested in the package brackets.
Does that help?