public void setMainApp(Main app) {
      this.app = app;
      
      toggleMitarbeiter.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/system-users.png"))));
      toggleDienste.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/accessories-calculator.png"))));
      toggleDienstplan.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/accessories-text-editor.png"))));

	  menuOpen.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/document-open.png"))));
	  menuSave.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/document-save.png"))));
	  menuQuit.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/system-log-out.png"))));
	  menuDelete.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/edit-delete.png"))));
	  menuOptions.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/preferences-system.png"))));
	  menuLanguage.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/text-x-generic.png"))));
	  menuHelp.setGraphic(new ImageView(new Image(this.app.getClass().getResourceAsStream("/resources/icons/weather-clear.png"))));
  }