I'm having a problem in flex 3 where if a static const I have defined is used as the parameter to a function call within binding tags I get a "1120: Access of undefined property NodePropertyMatrix". _propMtx is a ArrayCollection.

<mx:HBox visible="{_propMtx.getItemAt(NodePropertyMatrix.srcParent)}">

Above code throws the error, but the following code does not

<mx:HBox visible="{NodePropertyMatrix.srcParent}">

NodePropertyMatrix is an AS class as follows:

package model.constants
{
import mx.collections.ArrayCollection;

public class NodePropertyMatrix
{
    public static const srcParent:Number = 0;
}
}

Anyone know what is wrong here?