@Override
  public boolean isEnabledOnElements(PsiElement @NotNull [] elements) {
    if (elements.length == 1) {
      PsiElement member = findTargetMember(elements[0]);
      return member != null && getChangeSignatureHandler(member) != null;
    }
    return false;
  }
@Override
  public boolean isEnabledOnElements(PsiElement @NotNull [] elements)