question: public void valueChanged ( ListSelectionEvent e ) { if ( _table == null ) { return ; } int row = _table . getSelectedRow ( ) ; if ( log . isDebugEnabled ( ) ) { log . debug ( "Table valueChanged: row= " + row ) ; } if ( row >= 0 ) { _addButton . setEnabled ( true ) ; _addButton . setToolTipText ( null ) ; if ( _type != null && _type . equals ( "SignalHead" ) ) { makeIconMap ( _pickListModel . getBeanAt ( row ) ) ; clearIconPanel ( ) ; doIconPanel ( ) ; } } else { _addButton . setEnabled ( false ) ; _addButton . setToolTipText ( Bundle . getMessage ( "ToolTipPickFromTable" ) ) ; } validate ( ) ; }
target:  When a Pick list is installed, table selection controls the Add button