private void initGUI() { mainContainer = new BorderLayoutContainer(); refresButton = new TextButton("", ELearningController.ICONS.refresh()); removeFromLectureButton = new TextButton("Remove form lecture", ELearningController.ICONS.delete()); ListStore<Lecture> lectureListStore = new ListStore<Lecture>(lectureDataProperties.key()); lectureComboBox = new ComboBox<Lecture>( lectureListStore, new LabelProvider<Lecture>() { public String getLabel(Lecture item) { return item.getLectureName(); } }); ListStore<Professor> professorListStore = new ListStore<Professor>(professorProperties.key()); professorComboBox = new ComboBox<Professor>( professorListStore, new LabelProvider<Professor>() { public String getLabel(Professor item) { return item.getUsername(); } }); userGrid = createGrid(); ToolBar toolBar = new ToolBar(); lectureComboBox.setTriggerAction(ComboBoxCell.TriggerAction.ALL); lectureComboBox.setEditable(false); lectureComboBox.setAllowBlank(false); professorComboBox.setTriggerAction(ComboBoxCell.TriggerAction.ALL); professorComboBox.setEditable(false); professorComboBox.setAllowBlank(false); toolBar.setHorizontalSpacing(5); toolBar.add(refresButton); toolBar.add(new SeparatorToolItem()); toolBar.add(new Label("Professor: ")); toolBar.add(professorComboBox); toolBar.add(new Label("Lecture: ")); toolBar.add(lectureComboBox); toolBar.add(new SeparatorToolItem()); toolBar.add(removeFromLectureButton); mainContainer.setNorthWidget(toolBar, new BorderLayoutContainer.BorderLayoutData(30)); mainContainer.setCenterWidget(userGrid); setState(ManageEnrolledStudentsController.IManageEnrolledStudentsState.NONE); }