data = new FormData();
data.top = new FormAttachment(combo, 10);
data.left = new FormAttachment(atLabel, 10);
endPeriodText.setLayoutData(data);
combo.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event arg0) {
if (combo.getSelectionIndex() == 0) {
periodLabel.setEnabled(true);
startPeriodText.setEnabled(true);
atLabel.setEnabled(true);