ViewerDialog dialog = new ViewerDialog(null);
String filename = m_List.getSelectedValue().toString();
int result;
try {
DataSource source = new DataSource(filename);
result = dialog.showDialog(source.getDataSet());
// nasty workaround for Windows regarding locked files:
// if file Reader in Loader is not closed explicitly, we cannot
// overwrite the file.
source = null;
System.gc();