         ResourceManager.getInstance();
     
     // Arrays that keep track of children spanning
-    // content size columns or rows or whether the elements don't
-    // use columns or rows at all
+    // content size columns or rows or whether the 
+    // elements don't use columns or rows at all.
     private var colSpanElements:Vector.<ElementConstraintInfo> = null;
     private var rowSpanElements:Vector.<ElementConstraintInfo> = null;
     private var otherElements:Vector.<ElementConstraintInfo> = null;
     
-    private var constraintCache:Dictionary = new Dictionary(true);
+    private var constraintCache:Dictionary = null;
     
     //--------------------------------------------------------------------------
     //

    }
    
    /**
     *  wrapper for parsing all the element constraints
     */
    private function parseConstraints():void
    {

            var elementInfo:ElementConstraintInfo = otherElements[i];
            var layoutElement:ILayoutElement = elementInfo.layoutElement;
            
            // Only measure width if not constrained to columns.
            if (!(elementInfo.leftBoundary || elementInfo.rightBoundary))
            {
                var left:Number = elementInfo.left;
                var right:Number = elementInfo.right;
                var extX:Number;
                
                if (!isNaN(left) && !isNaN(right))
