@Override
		public void valueChanged(ListSelectionEvent e) {
			if (!e.getValueIsAdjusting()) {
				Object sel = lstStocks.getSelectedValue();
				if (sel != null && sel instanceof Stock) {
					btnOk.setEnabled(true);
				}
				else {
					if (requiresStock) btnOk.setEnabled(false);
					else btnOk.setEnabled(true);
				}
			}
		}