private void showErrors(final FetchDataResult result) {
        final String childStreamText = lastResult.getSourceLocation().getOptChildType()
                .map(childType -> " (" + childType + ")")
                .orElse("");
        final String title = "Unable to display source ["
                + lastResult.getSourceLocation().getIdentifierString()
                + "]"
                + childStreamText;

        final String errorText = String.join("\n", lastResult.getErrors());
        textPresenter.setErrorText(title, errorText);
    }
Compare the {@link DataRange}s using on the from/to {@link Location};
stroom-core-client/src/main/java/stroom/data/client/presenter/SourcePresenter.java