[flexcoders] Expressions window is smarter?

[markgoldin_2000]

This my code:
 public function handleDataChanged(event:ListEvent):void 
{       
  data.person = selectedItem.data; 
  mx.core.Application.application.globalDataProviderToSave =  
listData.owner.dataProvider.source;
} 

Compiler does not like "listData.owner.dataProvider.source".
Neither run-time. But Expressions window would show correct DataGrid 
underlying data.
Same with listData.owner.dataProvider.
All I am saying it is comfusing  like hell ..........................