diff --git a/panoramix/forms.py b/panoramix/forms.py
index 814fc0e972..1d8bf565a0 100644
--- a/panoramix/forms.py
+++ b/panoramix/forms.py
@@ -17,7 +17,7 @@ class BetterBooleanField(BooleanField):
     """
     def __call__(self, **kwargs):
         html = super(BetterBooleanField, self).__call__(**kwargs)
-        html += u'<input type="hidden" name="show_brush" value="false">'
+        html += u'<input type="hidden" name="{}" value="false">'.format(self.name)
         return widgets.HTMLString(html)
 
 
diff --git a/panoramix/static/widgets/viz_nvd3.js b/panoramix/static/widgets/viz_nvd3.js
index 7a0ec8a29d..9c502ed74e 100644
--- a/panoramix/static/widgets/viz_nvd3.js
+++ b/panoramix/static/widgets/viz_nvd3.js
@@ -26,7 +26,6 @@ function viz_nvd3(slice) {
           chart.xAxis
             .showMaxMin(fd.x_axis_showminmax)
             .staggerLabels(true);
-          chart.showLegend(fd.show_legend);
         } else if (viz_type === 'bar') {
           chart = nv.models.multiBarChart()
               .showControls(true)
@@ -34,7 +33,6 @@ function viz_nvd3(slice) {
           chart.xAxis
             .showMaxMin(false)
             .staggerLabels(true);
-          chart.showLegend(fd.show_legend);
           chart.stacked(fd.bar_stacked);
 
         } else if (viz_type === 'dist_bar') {
@@ -46,11 +44,9 @@ function viz_nvd3(slice) {
           chart.xAxis
             .showMaxMin(false);
           chart.stacked(fd.bar_stacked);
-          chart.showLegend(fd.show_legend);
         } else if (viz_type === 'pie') {
           chart = nv.models.pieChart()
           colorKey = 'x';
-          chart.showLegend(fd.show_legend);
           chart.valueFormat(f);
           if (fd.donut) {
             chart.donut(true);
@@ -70,7 +66,6 @@ function viz_nvd3(slice) {
           chart.xAxis
             .showMaxMin(false)
             .staggerLabels(true);
-          chart.showLegend(fd.show_legend);
 
         } else if (viz_type === 'bubble') {
           var row = function(col1, col2){
@@ -79,7 +74,6 @@ function viz_nvd3(slice) {
           chart = nv.models.scatterChart();
           chart.showDistX(true);
           chart.showDistY(true);
-          chart.showLegend(fd.show_legend);
           chart.tooltip.contentGenerator(function (obj) {
             p = obj.point;
             var s = "<table>"
@@ -99,7 +93,10 @@ function viz_nvd3(slice) {
           chart.xAxis
             .showMaxMin(false)
             .staggerLabels(true);
-          chart.showLegend(fd.show_legend);
+        }
+        if ("showLegend" in chart) {
+            if ('show_legend' in fd)
+              chart.showLegend(fd.show_legend);
         }
 
         var height = slice.height();
diff --git a/panoramix/utils.py b/panoramix/utils.py
index 1a3b31ac0a..e98630ee36 100644
--- a/panoramix/utils.py
+++ b/panoramix/utils.py
@@ -202,8 +202,8 @@ def log_this(f):
         log = models.Log(
             action=f.__name__,
             json=json.dumps(d),
-            dashboard_id=d.get('dashboard_id'),
-            slice_id=d.get('slice_id'),
+            dashboard_id=d.get('dashboard_id') or None,
+            slice_id=d.get('slice_id') or None,
             user_id=user_id)
         db.session.add(log)
         db.session.commit()