diff --git a/elements/urth-viz-chart/urth-viz-chart.html b/elements/urth-viz-chart/urth-viz-chart.html
index ced4df3e..6ca854d2 100644
--- a/elements/urth-viz-chart/urth-viz-chart.html
+++ b/elements/urth-viz-chart/urth-viz-chart.html
@@ -175,7 +175,8 @@
         },
 
         behaviors: [
-            Polymer.IronResizableBehavior
+            Polymer.IronResizableBehavior,
+            Urth.JupyterWidgetBehavior
         ],
 
         listeners: {
@@ -205,6 +206,10 @@
             primary = primary || this.primary;
             secondary = secondary || this.secondary;
 
+            if (this.columns.length && datarows[0] && this.columns.length != datarows[0].length) {
+                this.displayErrorMessage("Warning: arity of columns does not match data");
+            }
+
             var columnSettings = this.columnSettings;
             var values = (datarows[0] || []).map(function (rows, i) {
                 var t = function (d, i) {