@Override
  public void apply(@NotNull SvnConfiguration conf) throws ConfigurationException {
    if (isEmptyOrSpaces(myMergeText1.getText())) {
      myMergeText1.requestFocus();
      throw new ConfigurationException(message("source.url.could.not.be.empty.error.message"));
    }

    if (isEmptyOrSpaces(myMergeText2.getText())) {
      myMergeText2.requestFocus();
      throw new ConfigurationException(message("source.url.could.not.be.empty.error.message"));
    }

    if (myMergeText1.getText().equals(myMergeText2.getText()) && myRevision1.getRevisionText().equals(myRevision2.getRevisionText())) {
      throw new ConfigurationException(message("no.differences.between.sources.error.message"));
    }

    MergeRootInfo rootInfo = conf.getMergeRootInfo(myRoot.getIOFile(), myVcs);
    rootInfo.setUrl1(myMergeText1.getText());
    rootInfo.setUrl2(myMergeText2.getText());
    rootInfo.setRevision1(myRevision1.getRevision());
    rootInfo.setRevision2(myRevision2.getRevision());
  }
@Override
  public void apply(@NotNull SvnConfiguration conf)