return null; //it starts in a valid state
};
};
if (dialog.open() == Window.OK) {
Tuple<String, String> keyAndValueEntered = dialog.getKeyAndValueEntered();
if (keyAndValueEntered != null) {
vars.put(keyAndValueEntered.o1, keyAndValueEntered.o2);
treeItem.setText(1, keyAndValueEntered.o2);
}