from inside a project with existing ant :
- the Ant Build does not report any error whien building.
- Editing a source belonging to project, the following code :

    private boolean isDataNode ( Object source )
    { 
****> if ( source instanceof XmlTag ) // Direct coming from Xml jedit Pluggin
        return true ; 
      else if ( source instanceof DataModelPropertyElement ) // Node 
encapsulated
        return true ; 
      return false ; 
    }

reports 'inconvertible types found : java.land.Object required : 
xml.parser.XmlTag' on line marked with ****> from inside the editor with the 
corresponding line marked as error