rem: QWidget* KMFilterActionIdentity::createParamWidget(KMGFilterDlg* aParent)
add: QWidget* KMFilterActionForward::createParamWidget(KMGFilterDlg* aParent)
context: QWidget* KMFilterActionIdentity::createParamWidget(KMGFilterDlg* aParent){  QStringList ids = KMIdentity::identities();  QComboBox *cbx = aParent->createCombo( &ids, id );  return cbx;}