diff --git a/hoot-core/src/main/cpp/hoot/core/visitors/UniqueElementIdVisitor.h b/hoot-core/src/main/cpp/hoot/core/visitors/UniqueElementIdVisitor.h
index 9c79d91..dfe6565 100644
--- a/hoot-core/src/main/cpp/hoot/core/visitors/UniqueElementIdVisitor.h
+++ b/hoot-core/src/main/cpp/hoot/core/visitors/UniqueElementIdVisitor.h
@@ -35,6 +35,8 @@ namespace hoot
/**
* Returns a set of the element ids visited.
+ *
+ * @todo It may be possible to combine this with ElementIdsVisitor.
*/
class UniqueElementIdVisitor : public ConstElementVisitor
{