// TODO: we'll have to be smarter about this!
$this->mSections = array_merge( $this->mSections, $source->getSections() );
- $this->mTOCHTML = $this->mTOCHTML . $source->mTOCHTML;
+ $this->mTOCHTML .= $source->mTOCHTML;
// XXX: we don't want to concatenate title text, so first write wins.
// We should use the first *modified* title text, but we don't have the original to check.