diff --git a/src/matrix/joined_dataset.js b/src/matrix/joined_dataset.js
index 2b4f018debe5491983cddcd7df30096deddbecc8..c43dbeb21012cac4602ae7baccbd81677f6ac922 100644
--- a/src/matrix/joined_dataset.js
+++ b/src/matrix/joined_dataset.js
@@ -72,6 +72,7 @@ morpheus.JoinedDataset = function(dataset1, dataset2, dataset1Field,
 	}
 	this.dataset1 = dataset1;
 	this.dataset2 = dataset2;
+	// TODO put series in same order
 	var maxSeriesCount = Math.max(this.dataset1.getSeriesCount(), this.dataset2
 			.getSeriesCount());
 	for (var i = this.dataset1.getSeriesCount(); i < maxSeriesCount; i++) {
@@ -251,4 +252,4 @@ morpheus.JoinedMetadataModel.prototype = {
 	getMetadataCount : function() {
 		return this.vectors.length;
 	}
-};
\ No newline at end of file
+};