* cause a NullPointerException because leaf.valueMap is empty. Rest of the validation is the same as in {@link EvaluateExperimentsAction.validate}
* Since validate is protected we cannot call IEvaluateExperiments.validate.
*/
public boolean validate(boolean showValidationErrors) {
EvaluationStatus evaluationStatus = selectedPlan.getTree().getRoot().getEvaluationStatus();
if (evaluationStatus != EvaluationStatus.COMPLETE) {
FacesMessages.instance().add(FacesMessage.SEVERITY_ERROR, "Experiments have not been conducted.");
return false;
}