@Override
  public boolean isAvailable(@NotNull Project project,
                             @NotNull PsiFile file,
                             @NotNull PsiElement startElement,
                             @NotNull PsiElement endElement) {
    PsiClass classToExtendFrom = myClassToExtendFromPointer != null ? myClassToExtendFromPointer.getElement() : null;

    return
      super.isAvailable(project, file, startElement, endElement)
      && classToExtendFrom != null
      && classToExtendFrom.isValid()
      && classToExtendFrom.getQualifiedName() != null
      ;
  }
@Override
  public boolean isAvailable(@NotNull Project project,
                             @NotNull PsiFile file,
                             @NotNull PsiElement startElement,
                             @NotNull PsiElement endElement)