Fixes SORMAS-Foundation#3348 null value in create Event Actions

Author: syntakker

sormas-ui/src/main/java/de/symeda/sormas/ui/action/ActionEditForm.java

@@ -24,7 +24,6 @@
 import static de.symeda.sormas.ui.utils.LayoutUtil.locs;
 
 import com.vaadin.v7.ui.ComboBox;
-import com.vaadin.v7.ui.Field;
 import com.vaadin.v7.ui.Label;
 import com.vaadin.v7.ui.RichTextArea;
 import com.vaadin.v7.ui.TextField;
@@ -162,18 +161,16 @@ private void updateByCreating() {
 	}
 
 	private void updateByActionContext() {
-		NullableOptionGroup field = (NullableOptionGroup) getFieldGroup().getField(ActionDto.ACTION_CONTEXT);
-		ActionContext actionContext = (ActionContext) field.getNullableValue();
+		Object fieldValueActionContext = getFieldGroup().getField(ActionDto.ACTION_CONTEXT).getValue();
+		ActionContext actionContext = fieldValueActionContext == null ? null : (ActionContext) fieldValueActionContext;
 
 		// context reference depending on action context
 		// ready for adding new context
 		ComboBox eventField = (ComboBox) getFieldGroup().getField(ActionDto.EVENT);
 		if (actionContext != null) {
-			switch (actionContext) {
-			case EVENT:
+			if (actionContext == ActionContext.EVENT) {
 				FieldHelper.setFirstVisibleClearOthers(eventField);
 				FieldHelper.setFirstRequired(eventField);
-				break;
 			}
 		} else {
 			FieldHelper.setFirstVisibleClearOthers(null, eventField);