diff --git a/frontend/src/Editor/WidgetManager/configs/chart.js b/frontend/src/Editor/WidgetManager/configs/chart.js
index da6be05f6d..d5d2a12c36 100644
--- a/frontend/src/Editor/WidgetManager/configs/chart.js
+++ b/frontend/src/Editor/WidgetManager/configs/chart.js
@@ -179,9 +179,9 @@ export const chartConfig = {
   },
   exposedVariables: {
     show: null,
-    chartTitle: undefined,
-    xAxisTitle: undefined,
-    yAxisTitle: undefined,
+    chartTitle: null,
+    xAxisTitle: null,
+    yAxisTitle: null,
     clickedDataPoint: {},
   },
   definition: {