OPENOLAT-584: hide the date dependent configuration option in the qti node edit form

src/main/java/org/olat/course/nodes/iq/QTI21EditForm.java

@@ -128,6 +128,7 @@ public class QTI21EditForm extends FormBasicController {
 		testDateDependentEl.select("xx", testDateDependent);
 		testDateDependentEl.setHelpTextKey("qti.form.test.date.help", null);
 		testDateDependentEl.addActionListener(FormEvent.ONCLICK);
+		testDateDependentEl.setVisible(testDateDependent); // @UIBK: only show this option if it has already been configured
 	
 		Date startTestDate = modConfig.getDateValue(IQEditController.CONFIG_KEY_RESULTS_START_TEST_DATE);
 		startTestDateElement = uifactory.addDateChooser("qti_form_start_test_date", "qti.form.date.start", startTestDate, formLayout);