function getChildren(layt){ 
  //takes a layout as an argument
  var children = []; 
  var obj, order;
  //loop through all controls
  for (var id in _map) { 
    obj = _map[id]
    //check if control is on our layout
    order = layt.GetChildOrder( obj );
    if( order > -1 ) { 
      //got one!
      //zorder propery wll persist until getChildren called again
      //or manually overwritten by coder
      obj.zorder = order;
      children.push( obj ); 
    } 
  } 
  children.sort(function (a, b) { return a.zorder - b.zorder});
  return children; 
}