QTreeWidgetItem *branchWithFiles(const ChromTreeItem *cti_source) {
        bool keep = false;
        auto node = new QTreeWidgetItem();
        if(cti_source->isFileItem()) {
            keep = true;
        }
        for (int i = 0; i < cti_source->childCount(); i++) {
            auto *child = static_cast<const ChromTreeItem *>(cti_source->child(i));
            auto subbranch = branchWithFiles(child);
            if(subbranch) {
                node->addChild(subbranch);
                keep = true;
            }
        }
        if(!keep) {
            delete node;
            return nullptr;
        }
        node->setText(0, cti_source->text(0));
        if(cti_source->file) {
            node->setText(1, QString::number(cti_source->file->fileID()));
        }
        return node;
    }