private @Nullable PomTransaction getBlockingTransaction(PsiElement changeScope) {
    Stack<PomTransaction> blockedAspects = myTransactionStack.get();
    ListIterator<PomTransaction> iterator = blockedAspects.listIterator(blockedAspects.size());
    while (iterator.hasPrevious()) {
      PomTransaction transaction = iterator.previous();
      if (PsiTreeUtil.isAncestor(getContainingFileByTree(transaction.getChangeScope()), changeScope, false)) {
        return transaction;
      }
    }
    return null;
  }
private @Nullable PomTransaction getBlockingTransaction(PsiElement changeScope)