_conversationTableModel.setUrl(null);
_conversationModel.setUrl(null);
    private void treeCheckBoxActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_treeCheckBoxActionPerformed        if (treeCheckBox.isSelected() && _treeURL != null) {            _conversationTableModel.setUrl(_treeURL);        } else {            _conversationTableModel.setUrl(null);        }    }//GEN-LAST:event_treeCheckBoxActionPerformed