rem: void KMFilterActionRemoveHeader::setParamWidgetValue( QWidget* paramWidget ) const
add: void KMFilterActionAddHeader::setParamWidgetValue( QWidget* paramWidget ) const
context: void KMFilterActionRemoveHeader::setParamWidgetValue( QWidget* paramWidget ) const{  int idx = mParameterList.findIndex( mParameter );  ((QComboBox*)paramWidget)->clear();  ((QComboBox*)paramWidget)->insertStringList( mParameterList );  ((QComboBox*)paramWidget)->setCurrentItem( idx >= 0 ? idx : 0 );}