diff --git a/src/matrix/sort_key.js b/src/matrix/sort_key.js
index bccec30e99257714a0451d9d06cb2004710df6a1..a884813fd048f9697694870792e1e0f59a379270 100644
--- a/src/matrix/sort_key.js
+++ b/src/matrix/sort_key.js
@@ -1,4 +1,4 @@
-morpheus.MatchesOnTopSortKey = function(project, modelIndices, name) {
+morpheus.MatchesOnTopSortKey = function (project, modelIndices, name) {
 	var modelHighlight = {};
 	var p = project;
 	var viewIndices = [];
@@ -6,7 +6,7 @@ morpheus.MatchesOnTopSortKey = function(project, modelIndices, name) {
 		modelHighlight[modelIndices[i]] = true;
 		viewIndices.push(i);
 	}
-	this.comparator = function(i1, i2) {
+	this.comparator = function (i1, i2) {
 		var a = modelHighlight[i1] === undefined ? 0 : 1;
 		var b = modelHighlight[i2] == undefined ? 0 : 1;
 		return (a > b ? -1 : (a === b ? 0 : 1));
@@ -15,22 +15,22 @@ morpheus.MatchesOnTopSortKey = function(project, modelIndices, name) {
 	this.name = name;
 };
 morpheus.MatchesOnTopSortKey.prototype = {
-	init : function() {
+	init: function () {
 	},
-	getSortOrder : function() {
+	getSortOrder: function () {
 		return 2;
 	},
-	getComparator : function() {
+	getComparator: function () {
 		return this.comparator;
 	},
-	getValue : function(i) {
+	getValue: function (i) {
 		return i;
 	},
-	toString : function(i) {
+	toString: function (i) {
 		return this.name;
 	}
 };
-morpheus.SortKey = function(field, sortOrder) {
+morpheus.SortKey = function (field, sortOrder) {
 	if (typeof sortOrder === 'string') {
 		sortOrder = morpheus.SortKey.SortOrder[sortOrder.toUpperCase()];
 	}
@@ -42,16 +42,16 @@ morpheus.SortKey = function(field, sortOrder) {
 };
 
 morpheus.SortKey.SortOrder = {
-	ASCENDING : 0,
-	DESCENDING : 1,
-	UNSORTED : 2,
-	CUSTOM : 3,
-	TOP_N : 4
+	ASCENDING: 0,
+	DESCENDING: 1,
+	UNSORTED: 2,
+	CUSTOM: 3,
+	TOP_N: 4
 };
-morpheus.SortKey.ASCENDING_COMPARATOR = function(a, b) {
+morpheus.SortKey.ASCENDING_COMPARATOR = function (a, b) {
 	// we want NaNs to end up at the bottom
-	var aNaN = (a == null || _.isNumber(a) && isNaN(a));
-	var bNaN = (b == null || _.isNumber(b) && isNaN(b));
+	var aNaN = (a == null || _.isNumber(a) && isNaN(a) || a.length === 0);
+	var bNaN = (b == null || _.isNumber(b) && isNaN(b) || b.length === 0);
 	if (aNaN && bNaN) {
 		return 0;
 	}
@@ -71,10 +71,10 @@ morpheus.SortKey.ASCENDING_COMPARATOR = function(a, b) {
 	return (a === b ? 0 : (a < b ? -1 : 1));
 };
 
-morpheus.SortKey.DESCENDING_COMPARATOR = function(a, b) {
+morpheus.SortKey.DESCENDING_COMPARATOR = function (a, b) {
 
-	var aNaN = (a == null || _.isNumber(a) && isNaN(a));
-	var bNaN = (b == null || _.isNumber(b) && isNaN(b));
+	var aNaN = (a == null || _.isNumber(a) && isNaN(a) || a.length === 0);
+	var bNaN = (b == null || _.isNumber(b) && isNaN(b)) || b.length === 0;
 	if (aNaN && bNaN) {
 		return 0;
 	}
@@ -87,7 +87,7 @@ morpheus.SortKey.DESCENDING_COMPARATOR = function(a, b) {
 	return (a === b ? 0 : (a < b ? 1 : -1));
 };
 
-morpheus.SortKey.NUMBER_ASCENDING_COMPARATOR = function(a, b) {
+morpheus.SortKey.NUMBER_ASCENDING_COMPARATOR = function (a, b) {
 	// we want NaNs to end up at the bottom
 	var aNaN = (a == null || isNaN(a));
 	var bNaN = (b == null || isNaN(b));
@@ -103,7 +103,7 @@ morpheus.SortKey.NUMBER_ASCENDING_COMPARATOR = function(a, b) {
 	return (a === b ? 0 : (a < b ? -1 : 1));
 };
 
-morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR = function(a, b) {
+morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR = function (a, b) {
 	var aNaN = (a == null || isNaN(a));
 	var bNaN = (b == null || isNaN(b));
 	if (aNaN && bNaN) {
@@ -118,18 +118,18 @@ morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR = function(a, b) {
 	return (a === b ? 0 : (a < b ? 1 : -1));
 };
 
-morpheus.SortKey.STRING_ASCENDING_COMPARATOR = function(a, b) {
+morpheus.SortKey.STRING_ASCENDING_COMPARATOR = function (a, b) {
 	a = (a == null || a.toLowerCase === undefined) ? null : a.toLowerCase();
 	b = (b == null || b.toLowerCase === undefined) ? null : b.toLowerCase();
 	return (a === b ? 0 : (a < b ? -1 : 1));
 };
-morpheus.SortKey.STRING_DESCENDING_COMPARATOR = function(a, b) {
+morpheus.SortKey.STRING_DESCENDING_COMPARATOR = function (a, b) {
 	a = (a == null || a.toLowerCase === undefined) ? null : a.toLowerCase();
 	b = (b == null || b.toLowerCase === undefined) ? null : b.toLowerCase();
 	return (a === b ? 0 : (a < b ? 1 : -1));
 };
 
-morpheus.SortKey.ELEMENT_ASCENDING_COMPARATOR = function(obj1, obj2) {
+morpheus.SortKey.ELEMENT_ASCENDING_COMPARATOR = function (obj1, obj2) {
 	var a = +obj1;
 	var b = +obj2;
 	var aNaN = isNaN(a);
@@ -148,7 +148,7 @@ morpheus.SortKey.ELEMENT_ASCENDING_COMPARATOR = function(obj1, obj2) {
 		if (obj1.toObject && obj2.toObject) {
 			var a1 = obj1.toObject();
 			var b1 = obj2.toObject();
-			for ( var name in a1) {
+			for (var name in a1) {
 				a = a1[name];
 				b = b1[name];
 
@@ -162,7 +162,7 @@ morpheus.SortKey.ELEMENT_ASCENDING_COMPARATOR = function(obj1, obj2) {
 	return (a === b ? 0 : (a < b ? -1 : 1));
 };
 
-morpheus.SortKey.ELEMENT_DESCENDING_COMPARATOR = function(obj1, obj2) {
+morpheus.SortKey.ELEMENT_DESCENDING_COMPARATOR = function (obj1, obj2) {
 	// we want NaNs to end up at the bottom
 	var a = +obj1;
 	var b = +obj2;
@@ -181,7 +181,7 @@ morpheus.SortKey.ELEMENT_DESCENDING_COMPARATOR = function(obj1, obj2) {
 		if (obj1.toObject && obj2.toObject) {
 			var a1 = obj1.toObject();
 			var b1 = obj2.toObject();
-			for ( var name in a1) {
+			for (var name in a1) {
 				a = a1[name];
 				b = b1[name];
 				var c = (a === b ? 0 : (a < b ? 1 : -1));
@@ -193,20 +193,20 @@ morpheus.SortKey.ELEMENT_DESCENDING_COMPARATOR = function(obj1, obj2) {
 	}
 	return (a === b ? 0 : (a < b ? 1 : -1));
 };
-morpheus.SortKey.BOX_PLOT_SUMMARY_FUNCTION = function(array) {
+morpheus.SortKey.BOX_PLOT_SUMMARY_FUNCTION = function (array) {
 	var box = array.box;
 	if (box == null) {
 		var v = morpheus.VectorUtil.arrayAsVector(array);
 		box = morpheus
-				.BoxPlotItem(this.indices != null ? new morpheus.SlicedVector(
-						v, this.indices) : v);
+		.BoxPlotItem(this.indices != null ? new morpheus.SlicedVector(
+			v, this.indices) : v);
 		array.box = box;
 	}
 
 	return box.q3;
 };
 
-morpheus.SortKey.ARRAY_MAX_SUMMARY_FUNCTION = function(array) {
+morpheus.SortKey.ARRAY_MAX_SUMMARY_FUNCTION = function (array) {
 	var a = 0;
 	if (array != null) {
 		var aPosMax = -Number.MAX_VALUE;
@@ -231,8 +231,8 @@ morpheus.SortKey.ARRAY_MAX_SUMMARY_FUNCTION = function(array) {
 	}
 	return a;
 };
-morpheus.SortKey.ARRAY_ASCENDING_COMPARATOR = function(summary) {
-	return function(a, b) {
+morpheus.SortKey.ARRAY_ASCENDING_COMPARATOR = function (summary) {
+	return function (a, b) {
 		var aNaN = a == null;
 		var bNaN = b == null;
 		if (aNaN && bNaN) {
@@ -261,8 +261,8 @@ morpheus.SortKey.ARRAY_ASCENDING_COMPARATOR = function(summary) {
 	};
 };
 
-morpheus.SortKey.ARRAY_DESCENDING_COMPARATOR = function(summary) {
-	return function(a, b) {
+morpheus.SortKey.ARRAY_DESCENDING_COMPARATOR = function (summary) {
+	return function (a, b) {
 		var aNaN = a == null;
 		var bNaN = b == null;
 		if (aNaN && bNaN) {
@@ -291,54 +291,54 @@ morpheus.SortKey.ARRAY_DESCENDING_COMPARATOR = function(summary) {
 	};
 };
 
-morpheus.SortKey.reverseComparator = function(c) {
-	return function(a, b) {
+morpheus.SortKey.reverseComparator = function (c) {
+	return function (a, b) {
 		return c(b, a);
 	};
 };
 
 morpheus.SortKey.prototype = {
-	init : function(dataset) {
+	init: function (dataset) {
 		this.v = dataset.getRowMetadata().getByName(this.field);
 		if (!this.v) {
 			this.v = {};
-			this.v.getValue = function() {
+			this.v.getValue = function () {
 				return 0;
 			};
 			this.c = this.sortOrder === morpheus.SortKey.SortOrder.ASCENDING ? morpheus.SortKey.ASCENDING_COMPARATOR
-					: morpheus.SortKey.DESCENDING_COMPARATOR;
+				: morpheus.SortKey.DESCENDING_COMPARATOR;
 		} else {
 			var dataType = morpheus.VectorUtil.getDataType(this.v);
 			if (dataType === 'number') {
 				this.c = this.sortOrder === morpheus.SortKey.SortOrder.ASCENDING ? morpheus.SortKey.NUMBER_ASCENDING_COMPARATOR
-						: morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR;
+					: morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR;
 			} else if (dataType === '[number]') {
 				var summary = this.v.getProperties().get(
 						morpheus.VectorKeys.ARRAY_SUMMARY_FUNCTION)
-						|| morpheus.SortKey.ARRAY_MAX_SUMMARY_FUNCTION;
+					|| morpheus.SortKey.ARRAY_MAX_SUMMARY_FUNCTION;
 
 				this.c = this.sortOrder === morpheus.SortKey.SortOrder.ASCENDING ? morpheus.SortKey
-						.ARRAY_ASCENDING_COMPARATOR(summary)
-						: morpheus.SortKey.ARRAY_DESCENDING_COMPARATOR(summary);
+				.ARRAY_ASCENDING_COMPARATOR(summary)
+					: morpheus.SortKey.ARRAY_DESCENDING_COMPARATOR(summary);
 			} else {
 				this.c = this.sortOrder === morpheus.SortKey.SortOrder.ASCENDING ? morpheus.SortKey.ASCENDING_COMPARATOR
-						: morpheus.SortKey.DESCENDING_COMPARATOR;
+					: morpheus.SortKey.DESCENDING_COMPARATOR;
 			}
 		}
 	},
-	getComparator : function() {
+	getComparator: function () {
 		return this.c;
 	},
-	getValue : function(i) {
+	getValue: function (i) {
 		return this.v.getValue(i);
 	},
-	setSortOrder : function(sortOrder) {
+	setSortOrder: function (sortOrder) {
 		this.sortOrder = sortOrder;
 	},
-	getSortOrder : function() {
+	getSortOrder: function () {
 		return this.sortOrder;
 	},
-	toString : function() {
+	toString: function () {
 		return this.field;
 	}
 };
@@ -348,7 +348,7 @@ morpheus.SortKey.prototype = {
  * @param isColumnSort -
  *            sort columns by selected rows.
  */
-morpheus.SortByValuesKey = function(modelIndices, sortOrder, isColumnSort) {
+morpheus.SortByValuesKey = function (modelIndices, sortOrder, isColumnSort) {
 	this.field = 'selection';
 	this.bothCount = 10;
 	this.modelIndices = modelIndices;
@@ -358,16 +358,16 @@ morpheus.SortByValuesKey = function(modelIndices, sortOrder, isColumnSort) {
 
 };
 morpheus.SortByValuesKey.prototype = {
-	init : function(dataset, visibleModelIndices) {
+	init: function (dataset, visibleModelIndices) {
 		// isColumnSort-sort columns by selected rows
 		// dataset is transposed if !isColumnSort
 		this.dataset = morpheus.DatasetUtil.slicedView(dataset, null,
-				this.modelIndices);
+			this.modelIndices);
 		this.rowView = new morpheus.DatasetRowView(this.dataset);
 		this.summaryFunction = this.modelIndices.length > 1 ? morpheus.Median
-				: function(row) {
-					return row.getValue(0);
-				};
+			: function (row) {
+			return row.getValue(0);
+		};
 		if (this.sortOrder === morpheus.SortKey.SortOrder.TOP_N) {
 			var pairs = [];
 
@@ -377,8 +377,8 @@ morpheus.SortByValuesKey.prototype = {
 				var value = this.summaryFunction(this.rowView.setIndex(index));
 				if (!isNaN(value)) {
 					pairs.push({
-						index : index,
-						value : value
+						index: index,
+						value: value
 					});
 				} else {
 					missingIndices.push(index);
@@ -386,10 +386,10 @@ morpheus.SortByValuesKey.prototype = {
 			}
 			// sort values in descending order
 			pairs
-					.sort(function(a, b) {
-						return (a.value < b.value ? 1
-								: (a.value === b.value ? 0 : -1));
-					});
+			.sort(function (a, b) {
+				return (a.value < b.value ? 1
+					: (a.value === b.value ? 0 : -1));
+			});
 
 			var modelIndexToValue = [];
 			var nInGroup = Math.min(pairs.length, this.bothCount);
@@ -408,8 +408,8 @@ morpheus.SortByValuesKey.prototype = {
 				}
 				var indexCounterPairs = [];
 				for (var i = 0; i < nInGroup && bottomIndex >= 0; i++, bottomIndex--, counter++) {
-					indexCounterPairs.push([ bottomPairs[bottomIndex].index,
-							counter ]);
+					indexCounterPairs.push([bottomPairs[bottomIndex].index,
+						counter]);
 				}
 				for (var i = indexCounterPairs.length - 1, j = 0; i >= 0; i--, j++) {
 					var item_i = indexCounterPairs[i];
@@ -429,14 +429,14 @@ morpheus.SortByValuesKey.prototype = {
 			delete this.modelIndexToValue;
 		}
 	},
-	getComparator : function() {
+	getComparator: function () {
 		return this.c;
 	},
-	getValue : function(i) {
+	getValue: function (i) {
 		return this.modelIndexToValue ? this.modelIndexToValue[i] : this
-				.summaryFunction(this.rowView.setIndex(i));
+		.summaryFunction(this.rowView.setIndex(i));
 	},
-	setSortOrder : function(sortOrder) {
+	setSortOrder: function (sortOrder) {
 		if (typeof sortOrder === 'string') {
 			sortOrder = morpheus.SortKey.SortOrder[sortOrder.toUpperCase()];
 		}
@@ -450,10 +450,10 @@ morpheus.SortByValuesKey.prototype = {
 		}
 
 	},
-	getSortOrder : function() {
+	getSortOrder: function () {
 		return this.sortOrder;
 	},
-	toString : function() {
+	toString: function () {
 		return 'values';
 	}
 };
@@ -467,7 +467,7 @@ morpheus.SortByValuesKey.prototype = {
  * @param name
  *            This sort key name
  */
-morpheus.SpecifiedModelSortOrder = function(modelIndices, nvisible, name) {
+morpheus.SpecifiedModelSortOrder = function (modelIndices, nvisible, name) {
 	this.nvisible = nvisible;
 	var modelIndexToValue = [];
 	for (var i = 0, length = modelIndices.length; i < length; i++) {
@@ -478,27 +478,27 @@ morpheus.SpecifiedModelSortOrder = function(modelIndices, nvisible, name) {
 	this.c = morpheus.SortKey.ASCENDING_COMPARATOR;
 };
 morpheus.SpecifiedModelSortOrder.prototype = {
-	init : function(dataset) {
+	init: function (dataset) {
 	},
-	getComparator : function(a, b) {
+	getComparator: function (a, b) {
 		return this.c;
 	},
-	getValue : function(i) {
+	getValue: function (i) {
 		return this.modelIndexToValue[i];
 	},
-	setSortOrder : function(sortOrder) {
+	setSortOrder: function (sortOrder) {
 		this.sortOrder = sortOrder;
 		this.c = this.sortOrder === morpheus.SortKey.SortOrder.ASCENDING ? morpheus.SortKey.NUMBER_ASCENDING_COMPARATOR
-				: morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR;
+			: morpheus.SortKey.NUMBER_DESCENDING_COMPARATOR;
 	},
-	getSortOrder : function() {
+	getSortOrder: function () {
 		return this.sortOrder;
 	},
-	getName : function() {
+	getName: function () {
 		return this.name;
 	}
 };
-morpheus.SortKey.keepExistingSortKeys = function(newSortKeys, existingSortKeys) {
+morpheus.SortKey.keepExistingSortKeys = function (newSortKeys, existingSortKeys) {
 	// keep MatchesOnTopSortKey and dendrogram
 	// var existingOnTopSortKey = null;
 	var existingSpecifiedSortKey = null;
@@ -508,7 +508,7 @@ morpheus.SortKey.keepExistingSortKeys = function(newSortKeys, existingSortKeys)
 		// existingOnTopSortKey = key;
 		// }
 		if (key instanceof morpheus.SpecifiedModelSortOrder
-				&& key.name === 'dendrogram') {
+			&& key.name === 'dendrogram') {
 			existingSpecifiedSortKey = key;
 		}
 	}
@@ -521,7 +521,7 @@ morpheus.SortKey.keepExistingSortKeys = function(newSortKeys, existingSortKeys)
 			// newSortKeysHasTopSortKey = true;
 			// }
 			if (key instanceof morpheus.SpecifiedModelSortOrder
-					&& key.name === 'dendrogram') {
+				&& key.name === 'dendrogram') {
 				newSortKeysHasSpecifiedSortKey = true;
 			}
 		}
@@ -536,31 +536,31 @@ morpheus.SortKey.keepExistingSortKeys = function(newSortKeys, existingSortKeys)
 };
 /**
  * Group by key
- * 
+ *
  * @param values
  */
-morpheus.SpecifiedGroupByKey = function(clusterIds) {
+morpheus.SpecifiedGroupByKey = function (clusterIds) {
 	this.clusterIds = clusterIds;
-	this.c = function(a, b) {
+	this.c = function (a, b) {
 		return (a === b ? 0 : // Values are equal
-		(a < b ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
-		1));
+			(a < b ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
+				1));
 	};
 };
 morpheus.SpecifiedGroupByKey.prototype = {
-	init : function(dataset) {
+	init: function (dataset) {
 	},
-	getComparator : function(a, b) {
+	getComparator: function (a, b) {
 		return this.c;
 	},
-	getValue : function(i) {
+	getValue: function (i) {
 		return this.clusterIds[i];
 	},
-	setSortOrder : function(sortOrder) {
+	setSortOrder: function (sortOrder) {
 	},
-	getSortOrder : function() {
+	getSortOrder: function () {
 	},
-	getName : function() {
+	getName: function () {
 		return 'Dendrogram Cut';
 	}
-};
\ No newline at end of file
+};