private static @Nullable @Nls String validateAttributeHandler(@NotNull XmlElement context, @NotNull String value) {
    if (value.startsWith("#")) {
      if (JavaFxPsiUtil.getControllerClass(context.getContainingFile()) == null) {
        return JavaFXBundle.message("no.controller.specified.for.top.level.element");
      }
    }
    else {
      if (JavaFxPsiUtil.parseInjectedLanguages((XmlFile)context.getContainingFile()).isEmpty()) {
        return JavaFXBundle.message("javafx.annotator.page.language.not.specified");
      }
    }
    return null;
  }
private static @Nullable @Nls String validateAttributeHandler(@NotNull XmlElement context, @NotNull String value)